They also share 50% of their Google AdSense revenue from ads shown on your profile and other pages that belong to you.
teaser/demo:
http://www.youtube.com/watch?v=gMCgUFfEeL0
Did I mention they're in private beta? You can wait till public beta, or you can use this invitation:
http://tinyurl.com/5hpnqu
See ya there, MMG