Anything that's copyright; be that videos, programs, etc. There's a lot of copyright material being shared on the network. But not all that's being shared is copyright. There's lots of material that's not copyright. eg: There's music bands that seek marketing/distribution of their music by sharing it online (I was aware of quite a few who do this.) There's amateur/semi-pro video producers who so the same. There's photographers who do the same. There's some programmers who do the same.
