Habeas Sues Spammers
Habeas, the company that aims to stop spam by embedding copyrighted and trademarked material in the headers of e-mail, is springing into action with cases against alleged infringers. [Antipixel]

I'll be watching this to see how it turns out. I remember hearing about Haebeas when they first appeared and thought it was an interesting idea. I actually just signed up this morning, and also set my mailer to colortag any message that uses it. I'm kind of curious to see who else is using this.