because people get banned a lot. that would have to be a requirement of a paid subscription to AD, i believe. it would really jack up the cost to run the servers.
faqman, do you mean posting your email address on this site & if so then read the forum rules which contains rule #10 that i posted here. 10. Don't post your email address to the forums! Spambots love dumb forum users who post their email addresses to public sites and grab those addresses and you will soon discover the wonders of penis enlargement kits and other really useful products posted daily to your inbox.
If you talk about users having email addresses ending with afterdawn.com, the maintenance of such system would easily become a nightmare and we couldnt ever match services like GMail in terms storage space. We have private messaging system and you rarely get junk via them, so, just get everybody on your contact list to start using AfterDawn's PMs instead of emails and your problem is solved ;-)
touche to everybody on all counts @ddp I've read the forum rules and besides who would post their email in the first place that doesn't deserve it