If youve ever asked for information online about a product or service, or signed up for an e-list or group membership on the Internet, and received a nearly instantaneous response in your e-mail inbox, an autoresponder program was responsible for delivering the reply.

Simply put, autoresponders are e-mail programs that send out a preset message in response to every incoming e-mail received. Some autoresponders, like sign-up services for e-groups and forums, are one-shot deals: a single response for every message received. Just about every Internet-based company uses autoresponders for a variety of purposes, from automating tasks that would otherwise take up hundreds of man-hours to building lists and tracking prospective leads.

Multiple autoresponders send a series of messages to received e-mail addresses on a predetermined, timed basis. For instance, a multiple autoresponder can be used to send an instant response, then a follow-up message three days later, then another five days after that, and so on. It can be programmed to send a message a day, one per week, twice monthly, or any interval that satisfies the purpose of the message series.