The common filesharers do need anonymity, it's at least desireable to anyone sharing pr0n, cracks or anything copyrighted. As to I2P's speed sure on adverage it is marginally slower, due to the encryption and routing, however it's still faster than tor and other simular projects. Really it slightly comprimises speed for safety and as a result there should be more content and sources (something most filesharing networks are greatly lacking).

True enough, most people don't give a **** about security and they pay heavy prices for such disregards. Problems (spam, virri, etc) with email are costing companies money and wasting users time.