This is the first time that MPAA has attacked against TV show piracy and the reason for the move is obvious -- sales of DVD "box sets" of TV shows are huge.
MPAA said in its press release: "On these sites, anyone in the world can download entire television seasons in a single click. Every television series depends on other markets -- syndication, international sales -- to earn back the enormous investment required to produce the comedies and dramas we all enjoy, and those markets are substantially hurt when that content is stolen."
These are the sites that were sued: ShunTV, ZonaTracker, Scifi-Classics, CDDVDHeaven, Braggin'Rights and #BT @ EFnet.
While the abovementioned sites are down, at least for now, you can still search for torrents (and torrent sites) using, for instance, TorrentTyphoon. TorrentTyphoon is a meta search engine which catalogs the contents of several trackers and provides a simple, yet effective interface for searching the sites.
Source: MPAA