http://www.limewire.com/english/content/userguide.shtml

This page will get you to the User guide and the FAQ which should tell you what you need. The more sources there are for a file, the quicker it is likely to download. It means that at that paricular moment, a number of different users are sharing the file, and the network cleverly choses which ones to upload from to get a fast transfer. I can't explain how ...; my mind doesn't work that way. The red letters have something to do with firewalls, I think, but I take no notice of them whatsoever as there is in my experience, no difference in the possibility of getting a sucessful d/l from a red or a black host.