On Flippa, the user names of the people who are bidding against you are obfuscated, so you only know them as bidder #X. If I remember correctly, you could see the names of your competition at Sitepoint, which was reassuring because you could do a background check if you felt something unusual was going on.
The reason I am asking this now is that I am bidding on a few sites at the moment, and I noticed that in one instance, a new bidder has emerged just before the end of the auction, drove the price over the reserve, and is now my only competition. I really don't think anything unethical is going on, but I have no way to know for sure.
I wonder if I am bidding against a shill bidder in any of these auctions, and I don't understand why Flippa would hide such important information from bidders. Can anyone come up with a good reason to hide that information, especially in light of the recent problems at other auction sites?