I don't use microsoft products anymore because I won't give any $$ to bill gates and his world domination plans.
I don't use bearshare because I won't give him any $$ towards his gnutella domination plans. He shut down XOLX for no reason and that sucks.
People should have a choice as to what clients they are willing to share files with.
All clients should allow the user to block any client he wants to.
This would also allow users to move to different areas on the network and find different files since this clustering started.
Code to do this is now available for Gnucleus, posted to the forum. It will be a simple job to apply it to any open source client.