[SamAtt]

The graph is skewed but to be fair Peer-to-Peer saw an upswing from 1999-2001 when the original Napster introduced the technology to the masses. Then declined for a while between Napster being shutdown and more decentralized systems taking hold.

[loup-vaillant]

And, there is the big, centralized, web-based, file sharing services like MegaUpload and RapidShare. Thanks to the silly asymmetry in our connections (and if you pay), they are faster than bittorrent based file sharing. Thanks to some laws (like HADOPI in France), they are legally safer than bittorent (for copyrighted work). I suspect bittorent based file sharing is losing ground to them.