Torrents - downloadable data files created by users of the online peer-to-peer file-sharing system BitTorrent - are a roaring success with software thieves and people too slack, or tight, to buy games, music or video content from a shop. The neat format for large, high-speed internet downloads gathered from multiple sources enables users to freely obtain cutting-edge content - from documentary filmmaker Michael Moore's new movie, Sicko, to the beta of Apple's latest Macintosh operating system upgrade, Leopard. That is, for now. In May, a federal judge in Los Angeles ordered TorrentSpy, which claims to operate the largest BitTorrent search-engine site ( www.torrentspy.com ), to track its users' activities. TorrentSpy has appealed the ruling. If implemented, the user logs would help the Motion Picture Association of America, which represents the big Hollywood film studios, gather evidence for its copyright-infringement lawsuit against the site. Last month, TorrentSpy set up a filtering system called FileRights to automatically remove pirated material from the site's search results. The possibility that the sites' internet protocol addresses could be turned over to the authorities may help deter copyright infringement on BitTorrent file-sharing networks. We should all be wary of toying with torrents. With some sites, you never know exactly what material is being sucked from cyberspace onto your hard drive until you open the file. I recently wanted to watch a documentary on Dennis Rader, the American serial killer known as the BTK strangler (the acronym stands for his modus operandi - bind, torture and kill). I downloaded a torrent that turned out to be a movie with a French soundtrack. So I advise anyone who tinkers with torrents to consider something less hazardous, such as cave diving. But if you must, the following are my three top torrent clients - programs used for preparing, requesting and transmitting any computer file over a network, using the BitTorrent protocol. BitComet ( www.bitcomet.com ) has some of the smuttiest advertising you will see on the internet. But the interface is clean and unflashy, a la Lime Wire (the peer-to-peer file-sharing client for the Java platform). A big attraction is its preview function, which shows what you are downloading before the process is complete. Sometimes the program crashes, so be prepared to assume the position - spread your fingers and hit Control-Alt-Delete. With luck, the bugs that make this client unstable will have been fixed by the time you read this. BitComet is constantly upgrading, which can be both a blessing and an annoyance. Azureus (azureus.sourceforge.net) sounds like the name of some dark Inca god. The site's graveyard black, granite and blue interface is impressive too. Unlike BitComet, Azureus offers rock-solid stability. It is easier to see what you're doing with Azureus because it presents bold screenshots, rather than squeezing information into geeky lists. This torrent client showcases some BBC programmes in its 'browse content' section, along with fast-loading trailers and short movies, and does not force direct advertising upon a user. The main catch with Azureus is greed. Detractors have called it a resource hog, which means it eats up large amounts of a personal computer's memory, processing power or storage when in use. It also offers far fewer choices when you search compared with other torrent clients. Like BitComet, the interface for ?Torrent ( www.utorrent.com ) will not win any beauty contests. It is built on pragmatic rather than aesthetic lines. But it is simple and uncluttered, unlike BitComet's distractingly suggestive advertisements. It also has an edge on Azureus because of its smaller footprint, typically using less than six megabytes of memory. More importantly, its search function yields more relevant files that come to you at faster speeds. What ?Torrent lacks is a preview pane, which could lead you to download embarrassing or incomprehensible content.