Extremebet and Rivalbet are Futurebets which is a rogue operator that has screwed players out of literally millions of dollars. That is why they were kicked off of Ongame. If you do a search here for Pokes Poker, Carnaval Poker and Bayou Poker among others you will see what I'm talking about. Here is what Casinomeister has to say about Futurebet:
http://www.casinomeister.com/rogue/n.../futurebet.php