If you dont know what rakeback is, heres a short definition. Online pokerrooms charge rake to play in their games, which is how they make money. Whenever you sign up to a poker site, the site who directed you there gets some of that rake for reffering you to the site. A rakeback site gives some of that rake back to you in the form of rakeback.
Heres my favorite rakeback site, they give rakeback to all the sites (expect
pokerstars who doesnt give rakeback) that accept US players. In addition to rakeback you can also recieve free gifts for signing up for sites
Poker Source Online
also my name is "acornsnuts" on thier so be sure to say high to me in the forum