Notorious file-sharing site The Pirate Bay has announced it will no longer host torrent files, opting instead to use magnet links, which are more difficult to track and shut down.
"Magnet is now default, Download torrent is now where the magnet links used to be," said the group on its blog. "The reason is the same as always: Magnets are now good enough to use, and it's not as easy to block as .torrent files. Also it saves us a huge amount of bandwidth!"
Torrents work by dividing the target file into small information chunks, found on an unlimited number of different hosts. The torrent holds information about the location of different pieces of the target file, so that when a client initiates a torrent download, the chunks can be reassembled into a usable form.
Unlike torrent files, magnet links do not hold information on the location of a resource but rather on the content of the file or files to which they link. In the case of BitTorrent, they contain just the hash tag of the torrent, which is then used to locate copies of the files among peers using a torrent client.
While torrents rely on trackers - servers that assist in the communication between peers - magnets use distributed hash tables (DHTs), which can find peers that are downloading the same files without communicating via a central BitTorrent tracker. This makes them harder to block and easier to share, and also means that bandwidth costs are a lot lower.
Moreover, many BitTorrent trackers have been subjected to raids and shutdowns due to claims of copyright infringement. The Pirate Bay stopped running its own server in 2009. While magnet files also enable illegal file-sharing, they could provide The Pirate Bay with a legal defence that it is merely providing a search service.
On the downside, magnet links may take longer than a torrent file to start, especially if only a handful of people are sharing a certain file. This is because the torrent file has to be fetched from other users instead of being downloaded directly from the site.
All the mainstream BitTorrent clients have started supporting magnet links, since The Pirate Bay announced that it was dropping its tracker technology in favour of DHT in 2009. However, this has not put an end to the organisation's legal problems.
Only last week, Finnish ISP Elisa blocked access to The Pirate Bay in response to an injunction issued by a Helsinki court at the request of the International Federation of the Phonographic Industry. The IFPI is asking for injunctions that would force two other major Finnish ISPs - TeliaSonera and DNA.
A court in The Hague has also ordered that The Pirate Bay must be blocked within 10 days by Dutch ISPs Ziggo and XS4ALL.