DomainKeys is yet another way Yahoo! brings untold misery and grief to email forgers everywhere. Without boring you with too many details, it's an Internet standard developed in large part at Yahoo! that lets us confirm whether emails are really from their claimed domain.

It's always a good idea, however, to double-check and make sure a message is really from who it claims to be (for example, an email from Yahoo! should be from "...@yahoo.com" and not from a spoof domain like "...@y9ho00oo.com").

If you're a postmaster interested in implementing DomainKeys to protect your domain, you can find more technical details at http://antispam.yahoo.com/ and implementation information at http://domainkeys.sourceforge.net.