BitTorrent Inc., the file-sharing startup whose underlying technology is responsible for much of the piracy that plagues Hollywood, is laying off its sales and marketing department. The immediate cause of the layoffs: A failure to sell the Torrent Entertainment Network, BitTorrent's attempt at an online media store, to Best Buy for a rumored $15 million. That deal fell apart, a BitTorrent insider believes, because of a recent FCC ruling on file sharing. CEO Doug Walker, who replaced troubled founder Bram Cohen last fall, had hinted at a rethink of the store in March. Walker's also said to be rethinking BitTorrent's "DNA" service, which sought to offer businesses a cut-rate online content-deliver service, using file-sharing technology to undercut Limelight and Akamai's prices. BitTorrent is now thinking about making the service free, which would certainly count as "cut-rate" — but also suggests that it hadn't had much success selling it.