Even though torrent trackers do not host content themselves, they often find themselves under attack from media conglomerates for helping people find pirated content. Other groups with similar services are finding themselves under attack as well, such as Cinematube and Ssupload. Both of these sites are being attacked by the MPAA.
The MPAA claims the sites make significant amounts of cash as a result of pointing people towards pirated content, and is now suing them both. This is getting a bit further from sites or servers that actually host pirated content. How much more abstract will it become? Will the MPAA and RIAA begin suing sites that link to sites that happen to link to pirated content? Will they sue people for merely mentioning pirated content? I'd hate to see a world where the MPAA fires off preemptive lawsuits at people they think might be pirates in the future. Maybe that's a little far, but I do wonder how much farther these conglomerate companies are willing to go.
After all, if the RIAA is willing to sue people who don't even own computers and the deceased, I'm beginning to think nothing is beneath them.