You basicly download a file let's take EF_Setup1.7, meanwhile you also upload some of the parts (mostly just kbs) of it. People think it's faster but it isn't. Simple but true. That's why it's called "filesharing".
If you do that with cracked software/music then you can get into serious trouble (especially in Germany) as you are also kinda "hosting" cracked software and music (even though these are just kbs). As long as you download legal stuff f.e. our Launcher & patches it should be fine.
My brother recently got caught at filesharing. He downloaded some shit from a fake torrent side that sold his IP to the lawyer's office of a big music company. So if you ask me I'll rather stick to downloading from filehosters.