Myspace, probably the bestknown social network, has been sued by Universal Music. The reason ? You can probably think of that yourself : copyright infringement. Interesting is that the real battle is behind all this : News Corp is the owner of Myspace. Fox and DirecTV are also part of the family. Universal Music on the other hand is owned by the Vivendi Group, a french company.

MySpace is primarily a social networking site and may be able to make the argument that it doesn't profit directly from uploaded music videos.(Ars Technica)

I guess that about says it all. We'll see what happens.