An autoresponder is a script that automates email replies. The script is triggered by user actions either on a site or when a user sends an email directly to another email with an autoresponder in place.
We use autoresponders to streamline their campaigns and cut down on the amount of work needed. For example, rather than emailing each individual who signs up for a newsletter, an autoresponder may send out a welcome email that other scripts have personalized.
However, as autoresponders have gotten more complex, marketers now use them in broader ways to maintain contact with subscribers. This use of email autoresponders is a form of marketing automation and is extremely effective at driving customer engagement.