if by sharing, you mean to share copyrighted materials... then that, of course, is illegal in the United States. however, those copyright laws do not apply in some countries, so check with your country's laws.
in general, there's nothing illegal about "sharing". for example, the technology behind bittorrent is legal.
but as with anything in life, its up to you what you do with it. example, guns are legal in the united states.. you can buy.. own.. carry a gun legally.. but someone with a gun could clearly do something illegal with it. the gun "itself" isn't illegal, but what you do with it can be.
so be responsible, and keep in mind, we dont support sharing copyrighted materials here.
