How do ISP know what files you are sharing?

Question

ISP are to send letters out to people who they suspect are downloading copy right material, they even are treatening to cut them off. Using file sharing software to share large files has always be very useful. How exactly do they know if it is copy right material or not?

Answer 1

they know what you are downloading  

Answer 2

Simple.

They don't.

Like the first guy said, they know you are using file-sharing software, so they are basically just covering their backside should you get busted stealing software/music etc. (however unlikely).

Answer 3

ISP's can see your IP and what IPs you connect to so its fairly simple to monitor what people are doing. Plus most ISP can see what you are downloading.

Answer 4

Because they know every single web site, page, etc that you are going to.

They know you are file sharing by the traffic structure of your connections. From there it is not too difficult to see what site you are on. In fact it is bloody easy.