Private trackers don’t want their content to spread out over the whole BitTorrent so only registered members can share these files. However, Bitcomet simply ignores the “private flag” of these torrents and makes the torrents available to non-registered members through the DHT layer. DHT layers are “peer-to-peer” trackers (I like to keep things simple), and these don’t require an ip bound passkey in order to share.
Currently ScT Torrent, Midnight Torrents, UkNova and TorrentIt.com will not accept Bitcomet users.