@Bryan C.
I am a realtor/investor in south Carolina, and I have kept an eye on quite a few properties on auction.com, but have never bought anything. To even be able to bid on a property you have to create an acct, and give them your cc information so they can put a $2,500 hold on your card as a binder. I have also noticed that most of these properties that I have kept an eye on have a reserve. The reserve is usually not met on the properties, and therefore the auction ends just to have it reappear in a week or so. I also know that on some of these online auction companies (hubzu included), that they can bid the price up higher on behalf of the seller. Also, many of the properties that I have seen in my area on auction.com are occupied, and they do not allow (legally) you to disturb the "tenant" to inspect the property. Last, from what I have noticed many of the properties (even if they are in good condition) are cash only offers. So far, I am not really impressed with the site. Maybe other people will comment with a success story. I have purchased properties on Hubzu.com, and the process was terrible, but I did end up getting a great deal. Best of luck.
Adam