Yeah, i dont think its hugely useful at the moment. I can think someone who compiles a list of all the large poker sites then scrapes the keyword results could get a fairly decent idea whats good to rank for.
Also, by spending about half an hour i figured out a ton of keywords that are easy to rank for and send a fair bit of traffic.
Also in reference to this:
http://trends.google.com/websites?q=...rroom.com&sa=N
Partypoker probably does have about 5 times the web traffic of all of the others. Go compare there alexa's. So far i think its fairly accurate. Its obvious there getting there data from the toolbar, probably not analytics. But you never know.