Last poster is only partly correct. It is based off the LimeWire code, but SwapNut is a "forced sharing" network, so all SwapNut users must share their files. This is probably what the previous poster was talking about when he/she said that they almost always got the files they wanted from SwapNut. Also, Swapnut shows it's users files first, again increasing the chances since you usually pick from the top choices when there are duplicate listings.

With LimeWire, you can choose not to share anything or set upload connections to 0.

I had to voice my opinion with all you bashers out there. It is LimeWire to an extent, but they have made it very much better at getting your files when you are downloading from other SwapNut users. Don't believe me, go try it.