A recent anonymous proposal specifies a system using timelocked Bitcoin transactions and chaumian ecash mints to create an economic incentive for BitTorrent users to seed files.
“If Bitcoin is the money for sending money around when people don’t you doing so, BitTorrent is the mechanism for moving data around when they don’t want you to. It’s always had a big problem though, one I’m sure anyone who has ever used it is quite familiar with. The seeding problem.”