This is all done using a function called magnet links. This allows you to join a torrent swarm without truly using a torrent file or a centralized tracker. TPB has converted all of their torrents to magnet links. TorrentFreak has a good article about the changes. This is why many people will be commenting about “problems” at The Pirate Bay. It’s not a problem but a change – a major change for the site but for most people it won’t affect them much at all.

Many of the popular clients can already use magnet links so the change won’t mean much for those using Azureus/Vuze or uTorrent, but those using the popular client Transmission on OS X and Ubuntu may have to grab a different client for use with TPB (and uTorrent is still working some bugs out of magnet link usage).  You can also try Magnetiser, a Firefox extension for using magnet links.

Other sites may be switching over as well (torrentz.com site started with a trackerless system), especially with TPB’s considerable influence on the peer-2-peer community. Hopefully client development will quickly include the magnet link function.

TL;DR – it’s a change. Grab a client that works with magnet links and The Pirate Bay will be back to normal for you.

UPDATE: Transmission devs have already stated they are reworking the new 1.8 version to include magnet link function. That was fast.