The problem with sharing files with others while using a cable modem, is that you sometimes have to settle for a poor doewnload when others are downloading from you. Your download relies on having a good upload rate to keep telling the server to send more information. If you have even one other person downloading from you, this slows down the “send more data” signals that you need to get files faster.
Watch how much faster your download goes when someone isn’t downloading from you.
Only one person has tried to download something from me, and it timed out (not my fault). I only have about 10 songs, anyway–the main reason I got it was so I could talk to racinchikki on the IM 
I have a second phone line so my puter is usually on and I leave napster on. One time I came in and there were 12 uploads going at the same time. I was impressed. They were all slow as shit but they were going. I don’t mind sharing but my hard drive space is limited. When I had all my mp3’s on my jukebox and allowed napster to pick them up it used up too much disc space. Now all I have on napster is what I have downloaded, about 300 or so files.