lol
OK. File sharing is making available for download by other parties (using a variety of softwares) copyright material, and downloading copyright material ones-self. This usually consists of movies and CD audio tracks and albums.
Unfortunately, the concerned parties will always go after the ISP account holder, and this may only change if (for instance) it is clear that their wireless connection was used without their knowledge. You would be fined .. and it would be a large amount .. maybe thousands :(
It really depends on the type of material and the amount made available.
Generally, people who use file-sharing software share what they download with other parties too.