This paper presents two kinds of attacks based on crawling the DHTs used for distributed BitTorrent tracking. First, we show how pirates can use crawling to rebuild BitTorrent search engines just a few hours after they are shut down (crawling for fun). Second, we show how content owners can use related techniques to monitor pirates' behavior in preparation for legal attacks and negate any perceived anonymity of the decentralized BitTorrent architecture (crawling for profit). We validate these attacks and measure their performance with a crawler we developed for the Vuze DHT. We find that we can establish a search engine with over one million torrents in under two hours using a single desktop PC. We also track 7.9 million IP addresses downloading 1.5 million torrents over 16 days. These results imply that shifting from centralized BitTorrent tracking to DHT-based tracking will have mixed results for the file sharing arms race. While it will likely make illicit torrents harder to quash, it will not help users hide their activities.