I'm with Adam
The purpose of the Pirate Bay is facilitate with exchanging pirate material - it's the site's intention. This obviously separates it from Google, Sony et. al, and I would expect in a legal way too. Although intention is often hard to prove in court, I don't think they'd have too much difficulty with the Pirate Bay as it's so blatent. I expect it to be shut down, just as the early music sharing sites were a few years back.