Murky, murky waters, my friend. The law is not abundantly clear in these matters.
It would be helpful if someone could post the specific statute file swappers are accused of breaking. There seems to be a lot of "the law says ..." and "they are breaking the law because ..." but no one, to my knowledge, has actually quoted chapter and verse here.
The law is very clear - what you cannot do is "share" your music with others and thereby skirting royalty payments to the artists. Places like Kazaa (sp?) are just providing the software and a lookup directory. So, if some one wants a song (illegally) they go to Kazaa look it up and are provided with a list of servers that can provide it. This Brianna was hosting one of those servers. How do we know it was her idea? Maybe it was Mommy's idea and used her daughter as a front. The daughter's only defense is that she didn't know that others were downloading from her, which is pretty lame.
The difference is that all of the examples you mentioned (except the ripping) are covered by the First Sale doctrine. The law is abundantly clear in those cases. A different exemption exists in the case of ripping a CD for personal use, but that is more murky.
No, if you lend a CD to a friend (which means you don't have it anymore until your friend returns it to you) you are not breaking the law. If you burn a copy of the cd and give that to your friend (which means you both now have a copy although only one copy has been purchased) you are breaking the law. If you "rip" the CD to listen to it on your MP3 player, you are not breaking the law. But if you then give the original CD to your friend, while you keep the MP3 files on your MP3 player (which again means you both now have a copy while only one copy has been purchased) you are breaking the law. Not really all that murky unless you choose to be intentionally obtuse.