They don't work!!! You made the right decision! They're a scam. The LW devs checked them out last year & found they were a scam & didn't work. There's different variations of them from different sites but all with the same uselessness. One site's user-feedback showed it actually caused system problems let alone didn't work! You were wise!

Apparently there's one that worked for Kazaa (so it's claimed) but the same concept definitely doesn't work for gnutella. You can only downld as fast as the sources you're connected to will allow (have available upload slots & available upload bandwidth.)