It's a way to track your dealings with people online, similar to having an Ebay account and having a positive status.
There are other ways to keep track of your transactions online, but Heatware seems to be pretty popular. And then there is Beerology, which I'm clueless about...I stick with Heatware.
www.heatware.com
At the very least, start an account now. IF you mind your P's and Q's, there are folks around here that will trust a newcomer, but beware....bad trading will be dealt with swiftly ( beware the Troll Slayer )
Gah, EvilRick beat me to it. I'll just slouch back over to community then......