Glossary Part IV: T through Z

Test group: An audience group in your account that contains up to 10 email addresses for the purpose of testing email campaigns before they're sent.

Trigger email or auto-responder: Messages sent automatically based on individual actions (like clicking on a link) or dates (like someone's birthday). (Read more about triggers here.)

Unsubscribe/opt out: The process of removing oneself from an email list, meaning the brand is no longer legally allowed to send that individual emails. A person can opt out at any time by clicking the opt out link at the bottom of a campaign.

Webview (private): The online version of an email, which a person can access by clicking on the 'see it online' link at the top of a campaign in their inbox. This varies slightly from the online version (public).

Whitelist: Adding an ESP's domain to a customer's server which allows email messages to be delivered regardless of spam filters.