Email Marketing Dictionary

The Glossary of Email Marketing Terms from Email Marketing Rules

50/50 split test: A type of A/B test exposing half your subscribers to one version of an email or landing page and the other half of your subscribers to another version and seeing which version performs better to inform future decisions; also see A/B testing and 10/10/80 split test

10/10/80 split test: A type of A/B test exposing 10% of your subscribers to one version of an email or landing page and another 10% of your subscribers to another version, seeing which version performs better, and then exposing the remaining 80% of your subscribers to that winning version; also see 50/50 split test and A/B testing

above the fold: The portion of an email that displays before a subscriber scrolls; also see below the fold

absolute list growth: A measure of the change in the number of subscribers on an email list over a period of time; also see engaged list growth and real list growth

A/B testing: Exposing a portion of your subscribers to one version of an email or landing page and another portion of your subscribers to another version to see which version performs better; also see 50/50 split test and 10/10/80 split test

acquisition: see list building

action-triggered email: Triggered email sent in response to a subscriber taking a particular action (e.g., making a purchase or abandoning a shopping cart); also see date-, inaction-, and machine-triggered emails

active consent: Permission indicated when a person explicitly acts to indicate that they want you to add them to your email list (e.g., checking an unchecked box); also see passive consent

active opt-in: see active consent

active signup: Unchecked opt-in boxes, blank email address fields, and other signup mechanisms where the subscriber has to take an action for the email signup process to proceed

active unsubscribe: When subscribers opt out either through an unsubscribe mechanism provided by the sender or through one provided by their inbox provider, including Report Spam buttons

adaptive email design: Email design approach that uses media queries to establish one or more breakpoints at set screen widths at which the email content is reformatted, rearranged, or hidden so it’s optimized for the subscriber’s screen size

alt text: Text coded into an <img> tag that is displayed when the image is blocked and when recipients mouse over the image, although support isn’t consistent across email clients

animated GIF: An image file that displays multiple images sequentially over time, sometimes in a loop

apology email: Sent in response to an error, mishap, or bad press, this email apologizes, explains any action taking place in response, and tries to make amends; also see correction email

app-based email: An email client that’s installed on a device; also see webmail

assumed opt-in: Automatically opting in customers to receive promotional emails

automated email: See triggered email

back-in-stock email notification: A message sent to an individual subscriber when a product comes back into stock in response to that person either browsing that product when it was out of stock or opting in to be notified when that out-of-stock product becomes available again

below the fold: The portion of an email that displays only after a subscriber scrolls; also see above the fold

best practices: Those practices that generally produce the best results or minimize risk

blacklist: A list of senders of spam, typically maintained by an independent organization, used by inbox providers to determine whether and where to deliver email

blocked: When an inbox provider prevents your emails from being delivered to their users

body content: The text, images, and other content inside your email that becomes visible once opened

body copy: see body content

bounced: When an inbox provider rejects an email because it was sent to an unknown email address (hard bounce) or because of a temporary condition like the recipient’s mailbox being full (soft bounce)

broadcast email: An email sent to all subscribers

browse abandonment email: A message sent to an individual subscriber in response to that person browsing certain pages of your website but not making a purchase

browse retargeting email: see browse abandonment email

bulked: see junked

bulletproof button: A non-graphical button created from styled and linked HTML text inside a table cell with a background color that suffers minimal or no degradation when email images are blocked

business conversion: see sales conversion

call-to-action (CTA): What a message asks a subscriber to do, but more specifically the buttons and links subscribers click to take action

campaign conversion: see email conversion

CAPTCHA: Anti-bot security mechanism for forms that include reCAPTCHA, No Captcha reCAPTCHA, and Invisible reCAPTCHA

challenger: In an A/B test, the design or process you are testing against your existing champion, hoping to see an improvement in performance; also see champion

champion: During an A/B test, your existing design or process; also see challenger

checkout abandonment email: A message sent to an individual subscriber in response to that person starting, but not completing, the checkout process

cinemagraph: A picture composed of both static images and one or more animated GIFs, which give motion, often subtle, to a small portion of the overall picture

click: When a subscriber selects a link or linked image in an email with a mouse, trackpad, tap of a touchscreen, etc. and visits the associated landing page

click reach: The percentage of your subscribers who clicked at least one of your emails over a period of time (e.g., over the past month or quarter)

click-to-open rate: Percentage of subscribers who opened an email that also clicked the content inside, which is calculated by dividing clicks by opens

confirmed opt-in (COI): see double opt-in

confirmed opt-in lite (COIL): The process of requiring new subscribers to confirm their signup by engaging with the emails sent to them early in the email relationship or else receive no additional emails

content filtering: When an inbox provider evaluates an email’s subject line and other content as part of its process to decide whether and where to deliver the mail

Controlling the Assault of Non-Solicited Pornography and Marketing Act of 2003 (CAN-SPAM): A law regulating commercial email messaging that forbids deceptive messaging, requires senders to include a working unsubscribe link and their mailing address in every email they send, and requires senders to honor opt-out requests quickly, among other things

conversion: see email conversion and sales conversion

conversion reach: The percentage of your subscribers that have converted through at least one of your emails over a period of time (e.g., over the past month or quarter)

correction email: Sent in the wake of an email with one or more errors in it, this updated version of the email notes at the beginning of the subject line and/or body copy that the email is a “correction” or “update”

customer journey: The sequence of potential touchpoints a customer persona might use during an interaction with a brand

customer journey map: Documenting all the different sequences of potential touchpoints each of your customer personas might use for every action during the customer lifecycle

customer lifecycle: The various and ever deeper types of interactions that a customer has with a brand, including awareness, consideration, purchase, usage, retention, and evangelism

date-triggered email: Triggered email sent in response to the arrival of a particular date (e.g., birthday) or a certain condition being met (e.g., product back in stock); also see action-, inaction-, and machine-triggered emails

dedicated IP address: An IP address from which only one company sends email, making that company solely responsible for the sender reputation of that address; also see shared IP address

defensive design: Design techniques that allow an email to communicate its message effectively when images are blocked

deliverability: All of the issues involved with getting commercial emails delivered to their intended recipients’ inboxes

delivered: When email makes it to the intended recipient’s inbox or junk folder, as opposed to being blocked

desktop-centric design: Email design approach that uses basic coding techniques to create a single email rendering that’s optimized for viewing on large-screened desktops, which can easily handle multi-column designs, small text, and tightly clustered links and buttons

device-targeted content: Using responsive email design to target subscribers with different content depending on the device that the email is displayed on

double entry confirmation: Requiring a would-be subscriber to enter their email address a second time in a confirmation field on a subscription form and requiring that the two entries match in order to reduce entry errors

double opt-in (DOI): A subscription process where a new email address is only added to your mailing address after the email address owner clicks a confirmation link in a subscription activation or opt-in confirmation request email that’s sent to them after they opt in via a form or checkbox

dynamic content: A portion of an email that contains different content for different groups of subscribers or individuals based on their geography, demographics, behavior, or other factors

e-append: see email address append

earned media: Media content produced by media outlets, bloggers, consumers, and other end users of a brand’s products or services about that brand and distributed via any platform, such as publicity, social sharing, word of mouth, and ratings and reviews; also see granted media, leased media, owned media, and paid media

email address acquisition source: See subscriber acquisition source

email address append: Using a data broker to add email addresses to your customer profiles that don’t have them

email authentication: A variety of methods that help inbox providers accurately identify email sent by a brand, including Domain Keys Identified Mail (DKIM), Sender Policy Framework (SPF), and Domain-based Message Authentication, Reporting & Conformance (DMARC)

email automation: Triggered emails, personalization, dynamic content, and other tools that send emails or add content to emails on a one-to-one or one-to-some basis without manual intervention according to rules established by a brand

email brief: A document that’s accessible to all email stakeholders that details key aspects of a planned email, including the send date, message, call-to-action, audience, trigger logic, etc.

email client: An application or web interface that displays emails and allows users to reply, forward, and interact with the content of the message

email content calendar: A calendar indicating when you’ll send or launch each of your emails, plus when you’ll review or update your triggered and transactional campaigns

email conversion: When a subscriber completes the action requested by an email’s call-to-action

email fatigue: When a subscriber opens a brand’s emails less frequently because previous emails disappointed them

email list: A list of the email addresses and other records associated with your subscribers

email marketing workflow: The people, process, and tools involved in conceiving, creating, testing, approving, sending, and analyzing the performance of an email

email metrics: Measurements of the effectiveness of your email marketing campaigns and overall program

email reader: see email client

email service provider (ESP): A commercial provider of email marketing services that allows their clients to manage their email lists, send messages, track the response of message recipients, and process opt-ins and opt-outs, among other capabilities

email template: Reusable, preformatted email file that includes all essential email elements, plus content blocks that can be switched out to create individual emails

email validation: A service that catches email addresses that are formatted improperly or contain common misspellings of domain names

email verification: A service that checks to see if an email address belongs to a real person using lists developed by the vendor

engaged list growth: A measure of the change in the number of subscribers who have engaged with at least one of your emails over a period of time; also see absolute list growth and real list growth

engagement: Opens, clicks, and other positive indications that a subscriber is finding value in receiving emails from a brand

envelope content: envelope content: The portion of an email that’s visible to subscribers before they open it, which generally includes the sender name, sent date, subject line, and preview text

express consent: see active consent

expressed preferences: The topics, activities and other things that subscribers tell you they are interested in; also see implied preferences

feedback loop (FBL): A mechanism through which inbox providers notify email senders of spam complaints by their subscribers using a standard Abuse Report Format (ARF), allowing senders to unsubscribe those subscribers

first-name personalization: Dynamically adding an email recipient’s first name to either the envelope or body copy of an email

fluid email design: Email design approach that uses 100% width images and table cells to have the email content expand to completely fill the subscriber’s screen, up to a max width that’s set using media queries

footer: The HTML text at the bottom of an email that includes the promotional fine print, legal language, unsubscribe link, mailing address, and other details

forward to a friend (FTAF): Providing a link in your email that takes subscribers to a form that allows them to forward all or a portion of your email to one or more people that they know

freemail: An email account that is available for free from Yahoo, AOL, Gmail, Outlook.com, or another inbox provider

from email address: The email address from which your emails are sent to your subscribers; in some email client, this appears next to or instead of your sender name

fully responsive email design: Email design approach that uses adaptive design’s breakpoints to reformat, rearrange, and hide email content at set screen widths and uses fluid design’s 100% width scaling to optimize the size of images, fonts, buttons, and other elements between those breakpoints

geofence: A boundary set up around a physical location that’s used to trigger messaging when a subscriber crosses it, either coming or going

geolocation-based messaging: Using a person’s mobile device or some other method to identify their physical location and then sending them email, push notifications, and other messaging because they approached or departed a predefined physical area

gift services footer: A secondary content block typically positioned just before the footer that pulls together links to gift guides, order-by deadlines, return policies and other important seasonal buying information

global filtering: When an inbox provider junks and blocks all email sent by a brand to any of its email users; also see subscriber-level filtering

graceful degradation: Using fallbacks to provide adequate email experiences when advanced coding, animated GIFs, images, HTML, and other elements aren’t supported

granted media: Media content produced by a brand and distributed to an audience the brand developed via an open platform controlled by multiple third parties, such as email and SMS; also see earned media, leased media, owned media and paid media

graphical text: Text that is part of an image; also see HTML text

header: The upper portion of an email that includes your brand’s logo

hero: see primary message

holiday header: A temporary, holiday-themed header design supporting the seasonal messaging of your emails

HTML text: Text from a limited number of fonts that are universally or widely supported across email clients; also see graphical text

HTML version or part: The HTML part of a multipart MIME email that supports images, a range of HTML text formatting, and other functionality; also see multipart MIME (Multipurpose Internet Mail Extensions) protocol and plain text version or part

HTML5 video: An HTML specification for playing video content that’s supported by some inbox providers, allowing these videos to play inside emails

hybrid email design: Email design approach that generates the effects of adaptive or fully responsive design without relying on media queries

image blocking: When inbox providers or subscribers don’t allow the images in an email to load

images-off mosaic: Using background colors on the cells of elaborate tables to create pixel art pictures that only display when images are blocked in your email

implicit opt-in: Opting in a person to receive promotional emails who shared their email address with you for another purpose, such as receiving a report

implied consent: see passive consent

implied preferences: The topics, activities, and other things that subscribers indicate they are interested in based on their interactions with your brand; also see expressed preferences

inaction-triggered email: Triggered email sent in response to a subscriber not having taken a particular action in a certain amount of time (e.g., no email opens or clicks in 6 months); also see action-, date-, and machine-triggered emails

inactive subscriber: A subscriber who has not opened or clicked in any of your emails in a long time; the opposite of an active or engaged subscriber

inactivity: A lack of action from a subscriber or customer over a period of time

inbox placement rate: The percentage of emails sent by a brand or from an IP address that reaches their intended recipients’ inboxes, as opposed to being blocked or junked, based on delivery to a panel or seed list

inbox provider: Providers of web-based, desktop, and mobile email inboxes that send, store, and organize messages for users and manage and block spam (e.g., Gmail, Outlook, etc.)

IP address warming: A process of building up a sender reputation on a new IP address by gradually ramping up the volume of email sent from it

junked: When inbox providers route emails to a recipient’s junk or spam folder

landing page: Webpage, app, and any other digital destination that subscribers are directed to when they click a call-to-action in an email

lapsed-customer email: see win-back email

leased media: Media content produced by a brand and distributed to an audience the brand developed via a closed platform controlled by a third party, such as Facebook, Twitter, and mobile app platforms; also see earned media, granted media, owned media, and paid media

linear email interactions: When a subscriber follows the ideal and most trackable interaction path to conversion; also see non-linear email interaction

liquid design: see fluid design

list building: The process of adding email addresses to your mailing list

list churn: Subscribers lost to unsubscribes, spam complaints, and bounces from email addresses that no longer work

list hygiene: Ensuring that your email list is free of invalid and undeliverable email addresses, role-based email addresses, spam traps, unconfirmed email addresses, and chronically inactive subscribers

list rental: Having a message sent on your behalf to an email list owned by someone else

list-unsubscribe: Optional coding that marketers can add to the <head> of their emails to enable native unsubscribe links offered by inbox providers

live content: Images and other email content that vary based on when the email is opened, what kind of device it’s opened on, and other factors

live text: see HTML text

loaded weight: The file size of the HTML coding of an email plus the total file size of all the images used in the email

local-level filtering: When an inbox provider junks and blocks all email sent by a brand to one of its email users; also see global filtering

machine-triggered emails: Triggered emails sent in response to the requirements or instructions of an internet-of-things device; also see action-, date-, and inaction-triggered emails

mailing list: see email list

mailstream: The emails resulting from a single opt-in or preference selection

malicious opt-outs: When a person uses your opt-out page to unsubscribe someone else without that person’s consent

malicious signups: When a person signs up to receive email from a brand using an address they know to be false, inaccurate, or a spam trap for the explicit purpose of harming that brand’s sender reputation

media queries: CSS that allows the rendering of an email’s content to vary depending on conditions such as screen size

mobile-aware email design: Email design approach that uses basic coding techniques to create a single email rendering that’s suitable for a range of screen sizes, but is deferential to smartphones

multipart MIME (Multipurpose Internet Mail Extensions) protocol: An email format standard that allows you to bundle an HTML version, plain-text version, and other versions of your email together in one package; the receiving device’s capabilities or the subscriber’s preferences then determine which version is displayed; also see HTML version or part and plain text version or part

multivariate testing: Similar to A/B testing, except multiple variations in an email or landing page are tested simultaneously, which requires lots of data to do accurately

native inbox links: Enabled by marketers, these links appear as part of the email client interface and perform a variety of actions

navigation bar: A row of links to important pages on your website

newsjacking: Leveraging the popularity of a news story, event, or cultural phenomena to promote yourself or your company

non-linear email interactions: When a subscriber takes a path to conversion that isn’t ideal and perhaps not trackable; also see linear email interactions

onboarding: The process of familiarizing new subscribers with your email program and your brand using your signup confirmation page and welcome emails

open: When the images in an email are loaded or rendered, which typically happens when a subscriber views an email with images enabled

open reach: The percentage of your subscribers that have opened at least one of your emails over a period of time (e.g., over the past month or quarter)

open subscription form: An email signup form that’s accessible without purchase, account creation, registration, etc.

opt down: When a subscriber chooses to receive a brand’s emails less frequently

opt up: When a subscriber chooses to receive a brand’s emails more frequently, either by receiving current communications more often or opting in to receive additional communications

opt-in confirmation request email: Part of a confirmed or double opt-in, this email requires a new subscriber to click a link in the email to confirm their signup or else they receive no additional emails

opt-in confirmation page: Webpage or app messaging that follows a successful email signup

opt-in e-append: When a brand sends an email to people asking them for permission to email them in the future; also see opt-out e-append

opt-in email marketing: Sending email only to those who have given you permission to do so; also see opt-out email marketing

opt out: see unsubscribe

opt-out e-append: When a brand sends an email to people informing them that they will continue to receive emails from the brand if they don’t opt out; ; also see opt-in e-append

opt-out email marketing: Sending email to those who have not given you permission to do so and requiring them to unsubscribe or mark your emails as spam if they don’t want to receive future emails; also see opt-in email marketing

opt-out page: see unsubscribe page

opt-out process: see unsubscribe process

opt over: When a subscriber opts into one of your other channels, such as social or mobile, during your email unsubscribe process

opt up: When a subscriber opts into additional mailstreams from a brand, whether via a preference center, loyalty program, or sister brands

owned media: Media content that’s produced by a brand and distributed to an audience the brand developed via a closed platform controlled by the brand, such as a brand’s website, brochures, in-store signage, and events; also see earned media, granted media, leased media, and paid media

paid media: Media content produced by a brand and distributed to an audience developed by a third party via a closed platform controlled by that third party, such as TV ads, radio ads, newspaper ads, billboards, search ads, and display ads; also see earned media, granted media, leased media, and owned media

panel: see seed list

passive consent: Permission indicated when a person does not act to keep you from adding them to your email list (e.g., not unchecking a pre-checked box); also see active consent

passive opt-in: see passive consent

passive signup: Prechecked opt-in boxes and other signup mechanisms where the subscriber has to take an action to stop the email signup process from proceeding

passive unsubscribe: When subscribers effectively opt out by either not engaging with your emails for a very long time or by abandoning their email account altogether, causing your emails to eventually hard bounce

permission: Actively or passively agreeing to receive promotional email

personalization: Including information that’s unique or particular to the recipient in the subject line or body copy of an email

pixel art: see mosaic

plain text version or part: The text-only part of a multipart MIME email that supports only text and some basic symbols; also see multipart MIME (Multipurpose Internet Mail Extensions) protocol and HTML version or part

post-click metrics: Browsing, carting, and other activities on your site that take place after someone clicks through one of your emails

preference center: Webpage that displays a subscriber’s email address and other details, such as profile information (i.e., zip code, etc.) and communication preferences (i.e., topics of interest, etc.), and allows them to make changes as well as unsubscribe

preheader text: Visible or hidden HTML text positioned at the very top of an email’s body content that is used to control what appears as preview text; also see preview text

preview pane: A window in some email clients that allows subscribers to view a smaller portion of an email than if the email were opened in its own window

preview pane banner: A banner placed right above or right below the header (or navigation bar, if used) in the body of an email so that the banner always appears above the fold

preview text: A portion of the first text from inside the email that some email clients display after the subject line in the inbox, when highlighting a new email’s arrival, or in other situations; part of an email’s envelope content; also see preheader text

primary message: The main message of an email, usually positioned at the top and larger than other messages in the email

pristine spam trap: Used to identify spammers, this email address is uncirculated and hidden on websites where only email address harvesting software will see it

private IP address: see dedicated IP address

product grid: A multi-column and usually multi-row layout where each grid cell contains a product image and other information, such as product name, brand, and price

progressive enhancement: A technique that provides improved rendering or advanced functionality in certain email environments

progressive profiling: Collecting additional demographic data and information about interests from subscribers by periodically prompting them to answer questions, take quizzes, or interact with a guided selling program

proof of consent: Details on how, when, and where a subscriber opted in to receive emails from your brand

quality assurance: Ensuring that email content is error-free and functions properly and that the intended subscribers receive that content at the intended time

rate limiting: see throttling

reactivate: see reengage

reactivation email: see reengagement email

reading pane: see preview pane

real list growth: A measure of the change in subscriber lifetime value of a list, this metric subtracts the value of subscribers lost over a period of time from the value of those gained during that period; also see absolute list growth and engaged list growth

re-confirmation email: see re-permission email

recovery module: A secondary content block usually positioned right before the footer that contains many links to different product categories, brands, or other areas of your website with the intent to appeal to subscribers who were uninterested in the other calls-to-action in the email

reengage: Getting a subscriber to open or click one of your emails after a long period of having not done so

reengagement email: A message sent to an individual subscriber in response to that person having not engaged with your emails in a long time in an effort to get them to engage again

relevance: How valuable a subscriber thinks your emails are—which is largely determined by how many emails you send, when they arrive, their content, and how they look and function within whichever email client is being used

rendering: How an email displays and functions in a particular email client; this can vary wildly from email client to email client

re-order email: see replenishment email

re-permission email: A message that asks a subscriber to reconfirm their subscription by clicking a link in the email in order to remain on your active mailing list

replenishment email: A message sent to an individual subscriber in response to a product that person purchased being near or at its recommended or typical lifespan, maximum number of usages or servings, etc.

reply-to email address: Replies to your emails go to this address instead of your from email address

responsive email design: A variety of email design approaches that use media queries and other progressive enhancement techniques to control the formatting, layout, and display of email content depending on the subscriber’s screen size; see fully responsive email design, adaptive email design, hybrid email design, and fluid email design

responsive-aware email design: Email design approach that uses responsive email design for the header, navigation bar, recovery module, and footer of an email, and uses mobile-aware email design for the rest of the email

rich email content: Video consoles and other email content that subscribers can interact with without leaving their inbox

role-based email address: An email address that begins with info@, webmaster@, sales@, press@, support@, test@, or a similar function-based descriptor denoting that messages sent to this address are likely seen by or forwarded to more than one person

recycled spam trap: Used to identify spammers, this email address was created a user but abandoned long ago

sales conversion: When a customer or prospect makes a purchase or takes another action of monetary significance

scalable email design: see mobile-aware email design

S-curve: An easy-to-read layout where a content grouping with an image on the left and text on the right is followed on the next row down by a content grouping with text on the left and an image on the right, and so on

seasonality: Related to an upcoming or current season, holiday, or buying occasion

secondary message: The other message(s) in an email, usually following and smaller than the primary message

secondary navigation bar: Typically positioned right below your standard navigation bar, this one provides deeper navigation into one of your standard navigation bar links, links to seasonal merchandise and content, or links that support the primary message or theme of the email

seed list: When added to a sender’s email list, this software-monitored list of email addresses aids in determining whether emails sent by the sender are delivered to their subscribers’ inboxes

segmentation: Sending a particular message to only those subscribers who are likely to respond favorably based on geographic, demographic, psychographic, or behavioral factors; using a suppression list to avoid sending a particular message to certain subscribers; or sending a message at a time based on their time zone or geographic region

sender name: The name that appears in the from line in an email client

sender reputation: A reflection of your trustworthiness as an email sender that is affected by spam complaint rates and other factors that inbox providers use to determine whether to deliver, junk, or block your email

shared IP address: An IP address from which multiple companies send email, with all of them contributing to the sender reputation of that address; also see dedicated IP address

share with your network (SWYN): Functionality that allows subscribers to add content from your email to their social media timeline

shopping cart abandonment email: A message sent to an individual subscriber in response to that person leaving one or more unpurchased items in their shopping cart

short-supply email: see replenishment email

signup honeymoon: The period of heightened engagement right after a subscriber has opted in

single opt-in (SOI): A subscription process where a new email address is added to your mailing list without requiring the owner of that email address to confirm definitively that they knowingly and willingly opted in

snippet text: see preview text

snowshoeing: When a sender spreads their send volume across a large number of IP addresses in an attempt to evade inbox providers’ spam filters

social media bar: A row of social media icons that link to your brand’s pages on those social media sites

social sign-in: Using the login information from a social network to sign in to a third-party website

soft opt-in: see assumed opt-in

spam: Any email that recipients consider unwanted or irrelevant—even if it’s from brands they know and even if they gave the brand permission to email them

spam complaint: When an email recipient hits the Report Spam or Junk button, indicating to their inbox provider that the email was unwanted or irrelevant and that future emails from the sender are to be blocked

Spamhaus: An international nonprofit organization that tracks spam and related cyber threats and provides threat intelligence to inbox providers and other networks in the form of blacklists and other data

spam trap: These email addresses are used by inbox providers and blacklisting organizations to identify spammers; see pristine spam trap, recycled spam trap, and typo spam trap

split testing: see A/B testing

spongy email design: see hybrid email design

spoof: When spammers, phishers, and others falsify the sender name and address of an email, making it appear to come from a reputable person or brand in an attempt to deceive the recipient

statement of permission: A reminder of how the subscriber opted in to receive your emails and an explanation of why they received this particular email

static image: An image that doesn’t change over time, unlike an animated GIF

statistically significant: Having enough data from a test that the results are meaningful rather than simply the result of chance

still image: see static image

styled alt text: Alt text that has had its font type, size, weight, or color changed through the application of inline CSS styling

subject line: The text that appears in the subject line in an email client; part of an email’s envelope content

subject line quick link: A native inbox link positioned by the subject line that lets subscribers click through to the email’s primary landing page without opening the email

subscriber: Someone who has consented to joining your email list

subscriber acquisition source: The form or mechanism through which a subscriber opts in to receive emails from a brand, or the ad, sign, or other messaging that drove them to opt in

subscriber lifecycle: The various stages that a subscriber passes through from the time that they sign up until the time that they unsubscribe or otherwise cease receiving emails from a brand, including the stages of acquisition, onboarding, engagement, super-engagement, reengagement, and transition

subscriber journey: One but usually more segmented, triggered, or transactional emails designed to facilitate or improve a customer or subscriber interaction

subscriber lifetime value: The cumulative profit generated by a subscriber during their time on your list

subscriber replacement rate: The number of new subscribers a brand needs to add to its list over a period of time to replace those lost over that same period in order to maintain the size of its list

subscription activation request email: see opt-in confirmation request email

super-engagement: Tactics that further engage subscribers who are already highly engaged

suppression list: A list of subscribers to whom you don’t want a particular message to be sent

swipe file: A record of your top-performing emails, subject lines, calls-to-action, content blocks, landing pages, and other email elements that you return to for learnings and inspiration

system text: see HTML text

tap: see click

targeting: Achieving at least one facet of sending the right message to the right subscriber at the right time

throttling: When an inbox provider slows the rate or volume at which they accept a sender’s emails, or when a sender or email service provider manages the rate at which they send email to an inbox provider to avoid throttling or bounces

total weight: see loaded weight

total clicks: The number of times the links or linked images in an email were selected by subscribers, who then visited the associated landing page; a method of measuring opens that includes repeat clicks by an individual subscriber

total opens: The number of times the images of an email were loaded or rendered; a method of measuring opens that includes repeat opens by an individual subscriber

transactional email: A message sent to a current or former customer or user, regardless of whether they are a subscriber, in response to a transaction or administrative request made by that person or in response to a security, legal, or other company situation that may affect that person

triggered email: A message sent to an individual subscriber in response to an action taken by that person (e.g., cart abandoned), to a lack of action (e.g., reengagement), to the arrival of an event (e.g., birthday), or to the requirements or instructions of an internet-of-things (IoT) device (e.g., battery low); see action-triggered email, inaction-triggered email, and date-triggered email

typo spam trap: Used to identify spammers, this email address is one character off from legitimate email addresses so that it sometimes makes it onto marketers’ email lists due to entry errors by well-intentioned consumers

unique clicks: The number of subscribers who selected a link or linked image in an email at least once and visited the associated landing page; a method of measuring clicks that only counts the first click made by individual subscribers, ignoring any subsequent clicks

unique opens: The number of subscribers who loaded or rendered the images of an email at least once; a method of measuring opens that only counts the first open made by individual subscribers, ignoring any subsequent opens

unknown user: An email address that is invalid, either because the address never existed or because the address has been long abandoned

unsubscribe: When a subscriber requests to be removed from a brand’s email list

unsubscribe page: Webpage that is launched when subscribers click the unsubscribe link in your emails where subscribers complete the unsubscribe process

unsubscribe process: How subscribers remove themselves from your email list

video GIF: A compressed, streaming animated GIF capable of video-quality frame rates

webmail: An email client accessible via a web browser; also see app-based email

weight: The file size of the HTML coding of an email; also see loaded weight

welcome email: A message automatically sent to a new subscriber just after they’ve opted in that welcomes them to your email program and seeks further engagement; also see welcome email series

welcome email series: Multiple emails automatically sent to a new subscriber over time that seek to maximize engagement

win-back email: A message sent to an individual subscriber in response to that person having not made a purchase in a long time in an effort to get them to make a purchase again

withhold study: When a brand doesn’t send emails to a portion of their list for a period to measure what effect that lack of messaging has on that group’s spending across all channels compared to subscribers who continued to receive emails during that period