ah! Thanks sam. Luckily trap_jaw's summary here probably saved me hours of reading. I still plan to browse there more as time allows. Looks like "magnets" is the magic word for us on OSX. Now I have to find out what it means, and an OSX programmer!

BTW, I was reassured to see the Limewire team is active there--I was afraid the silence here since Christmas meant bad news for the company, and good news for those who would like to shut down these kinds of networks.