I just read about ChoiceMail, a whitelist-based email service that "turns your inbox into the equivalent of your front door" where people have to knock and identify themselves as human via a quick web form (hello, Cluetrain) before their message is allowed in. This is exactly the idea I've been tossing around in my head and reading about for some time now.
I would pay for this service in an instant, but unfortunately it apparently requires Windows. So, I just got SpamAssassin and Razor working on home IMAP server, so I think I might just poke at finally implementing a service like ?ChoiceMail on my own. Hell, maybe I'll even have it send me Jabber messages for permission confirmation and accept messages for whitelist additions, but keeping everything in the context of email seems better.shortname=ooobch