An autoresponder is a program or script on a mail server that automatically replies to e-mails. Though it is run from the mail server, an autoresponder can usually be set up by the user through a Web-based interface. For example, a company might set up an autoresponder for their support e-mail address to let users know they have received their support requests. The automated reply might read something like, "Thank you, we have received your message. One of our technicians will attempt to answer your question after he finishes his dart game in the lobby."
Individuals may also use autoresponders to let people know when they are away from their computer and won't be able to respond to any e-mails for awhile. For example, you might set up an autoresponder for your personal e-mail address to say, "Sorry, I am on vacation in the Bahamas indefinitely. I'll respond to your message whenever I decide to come back." Of course, it is important to reply to messages even after the autroresponder has sent a response. After all, most people like to communicate with other people rather than computers.