Sendio I.C.E. box

No, this has nothing to do with Immigration and Customs Enforcement, it is the new anti-spam solution from Sendio. The idea is pretty ingenious. When you send an email to my company, the I.C.E. box replies asking you to verify yourself. What spammer will actually try to verify their spam? This way only legitimate email gets verified. I still haven't figured out how automated email systems will work with this scenario (I know you can add whitelist entries to workaround, but seems a hassle) and the only other problem is explaining to end user's recipients why they have to verify themselves. I can see some emails never making it through this way.

http://www.sendio.com/