Oh--you mean "ultrapeer"

Most people run in leaf mode, and thus only connect to three other computers.

However, those three connect to ~64 others, and thus can spread your message to many many more people than you can.

This is what allows you to search 100's of thoudands of other computers at the same time without having to process all those messages.

So, the ones who have the stability, bandwidth and processing power are called Ultrapeers, and LW will automatically figure out if your setup is needed to help out.

If so, one day you may find you are running as an ultrapeer.

You shouldn't really notice much difference though. Currently running as an UP only uses up ~7 KB/s, and not much CPU%, but still more than a leaf would use.

No need to disable it--it will usually do so by itself if your bandwidth is already being heavily used by file transfers.