This is very strange, as I highly doubt they're crawling the entire DHT space, and even if they did they would be getting only infohashes. These are hashes of (

This is very strange, as I highly doubt they're crawling the entire DHT space, and even if they did they would be getting only infohashes. These are hashes of (a subset of) the torent metadata (including the chunk hashes), so it won't actually tell you what the content is, unless you also download the torrent metadata from peers using BEP-0009. I'd bet they're pulling popular torrent files from big sites and then pulling peer lists from the DHT. This will work OK for 'hot' content, but they could probably get much better lists if they actually connected to swarms and did peer exchange (PEX) which clients effectively have no control over - it's up to their peers if they are going to reveal addresses through PEX. Also note that of course none of this will work for private torrents (which almost all clients respect) as they disable all methods of peer/metadata acquisition other than from the trackers directly.