If you've 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.