The reason why PartyPoker was banned from google is, in my opinion, that they acquired several thousand links from other websites, within a very short period of time, trying to become the number 1 for the keyword “poker”. The problem was that they put about 200 or more outgoing links on each of hteir linkspages. I think that that was the reason they got penalized!
But, it’s just speculation on my part (getting penalized for that, I know that they did the exchange)