By using the excellent "tutorial" that pbreit (a regular member of the web2py google groups gang) and the pretty informative site of web2py slices (
http://www.web2pyslices.com/) pyForum, and qa-stack will soon offset their mail functionality to Amazon Simple Email Service (SES), you may read the recipe on:
http://www.web2pyslices.com/slices/take_slice/123I'll keep you posted.
PS The way email notifications, administrative contacts, etc, work is by "queuing" all the messages in our database, then you can use any external solution for content delivery. Also note that the "My Messages" functionality (internal member communications among forum members) does not use email for sending messages, it is a real-time process.