You may think that eBays user ratings are useless, Pete, but IMO, they are the one single thing that has made the on-line auction work for eBay. Yes, they can be manipulated to some extent, but not completely. What they are all about is giving you an insight into the reputation of a person you are considering a transaction with. In a small town, you hear about reputation because everyone talks about their dealings with their neighbors. In larger cities, you don't hear about reputation directly, and have to depend on longevity of a business to decide if you want to deal with them. eBay combines this, and gives you some info about how long a trading partner has been around under the same name, how many trades he has done, and how satisfied his trading partners were.

Not perfect, but better than any system any competitor has come up with, and has worked great for me as a buyer and as a seller.