mmmmmmmm, on http://en.wikipedia.org/wiki/BitTorrent it says "BitTorrent is one of the most common protocols for transferring large files, and peer-to-peer networks have been estimated to collectively account for approximately 43% to 70% of all Internet traffic (depending on geographical location)" so... 60% of requests are done by crawlers?

Have a beer and read a more insightful blog about this subject: http://blog.databigbang.com