So sick of hearing whining about the game being rigged.  Hell, you can get a simulator to test the shuffling algorithm: http://www.briggsoft.com/docs/pmavens/Utilities.htm#shuffle  That link also explains the shuffling algorithm used, and background on hand shuffling in general.  Trust me, it's solid -- the guy who wrote it definitely knew what he was doing.  It's impossible to rig by manipulating the cards dealt.  End of story.  The client used is closed source, and they'd have to muck with that source to do it -- and anyway, it would be discoverable in hand histories if you ran them through statistical analysis.

As for some sort of crazy colluding, like the site owners telling players at a table what other player's cards are... I think it might technically be possible, I'm not sure -- but I do know, based on the way the client serves up the hands of poker to players, it'd be a huge PITA, would probably lag the gameplay, and of course wouldn't worth the risk.  They make their money from rake, there's no way they'd risk the integrity of their entire site for a few extra bucks.