aWeber provides an offsite system for email autoresponders or ezines. Its a good solution if you will have a large list and do not want to put stress on your own server. They also take great care to get on the various "white lists" to ensure that your email gets though.

aMember no longer officially supports integration with aWeber, since aWeber does not like outside software that add emails automatically. To counter this its necessary to place the aweber signup on the thank you page, or before the signup page. More info on this is available to premium members.