"it's purpose is pretty obvious".

I don't think that's true. Clearly a lot of copyrighted material is downloaded from the site but there is a also a lot of material linked to legally. For example they now promote independent artists on their homepage who have content available on the pirate bay. Nine Inch Nails have a huge collection of unedited concert footage available. Open source software and Linux distros are available.

I think the 'linking to content is illegal' thing really needs to be seriously examined. Are they going to block Google next? Where is the line?

(And I'm saying this as someone who pays for content and really only does download legal content from TPB).