IsoHunt is still fighting its legal battle with the MPAA. In the latest episode, the torrent website filed a reply brief (PDF, via TorrentFreak) to the US Court of Appeals in which it suggests that Google, and not IsoHunt, is the largest BitTorrent search engine on the Internet.

IsoHunt is essentially arguing that if it is going to be targeted by movie studios, so should Google. Last month, Google got involved took interest in the ongoing court case between IsoHunt and the MPAA, fearing that the standing injunction could damage it. Although the search giant did not dispute IsoHunt's liability, the company is clearly concerned. Here's the crux of IsoHunt's argument:

Neither Google nor Plaintiffs mention the 95% overlap between torrents available through Defendants' systems and torrents available through Google and/or Yahoo!. (AOB 29-30.) Neither Google nor Plaintiffs mention the 96% of Torrentbox tracker users who get torrents from places other than the Torrentbox torrent site, such as from Google or Yahoo! (AOB 11.) Defendants might argue to the jury that it is unfair to hold Defendants liable if Google, unbothered by Plaintiffs, provides torrents to ten or twenty times the number of users that visit Defendants. Defendants might argue that Defendants are being scapegoated. Defendants might argue that holding Defendants liable while ignoring Google would not curtail infringement. Defendants might argue that Plaintiffs have litigation purposes other than curtailing infringement.

Through the appeal, IsoHunt hopes to reverse the permanent injunction which orders it to filter its search results, and obtain a jury trial instead of a summary judgment. In its reply brief, IsoHunt argues that the majority of the files that can be found through its search engine are also available via Google.

While Google is not a torrent search engine, it does index and cache hundreds of millions of pages with directs links to torrent files. There's even a filetype command that allows users to search only for torrent files (by specifying the .torrent extension).