The latest are things like metadata exchange and PEX, where you can get everything you need including the torrent file and a list of peers directly from the Bit

The latest are things like metadata exchange and PEX, where you can get everything you need including the torrent file and a list of peers directly from the BitTorrent DHT given only the SHA1 of the torrent file. This is the direction TPB has chosen, where they're only going to have those hashes and not host the torrent files at all. The entire TPB index will fit on a USB drive.