Grandpa, I actually use a very narrow definition of the term:
"Giving without expecting anything in return."
This excludes selling and trading. If you know any other definition that applies (to filesharing, not agriculture), let me know. Those who expect files in exchange for offering them are traders, pure and simple. While they are by no means unwelcome on LimeWire (don't take that to mean I speak for the network, haha), it would be foolhardy to optimize LimeWire for their use... especially when DirectConnect is already a network optimized for file trading.
While I agree with the definitions in your post, I don't see how they can be used to define sharing as "expecting something in return".
Cyberstalker, two things:
1) Perhaps you are right. BUT- as far as I know, the only successful filesharing network that didn't have heavy porn traffic was Napster, and it had a monopoly on userbase at the time. In any event, those who download porn usually share and download other things too, and alienating the porn fiends is not a good idea. They compose a larger percentage of the userbase (and shared files!) than you'd think.
2) I hope you're not some puritan who thinks porn has no place on the internet. If so, come out and state it plainly, so I can verify that you're a fool. Otherwise, my apologies for calling you a puritan.