Teli,
I know this thread is old. But, I have sold quiet a few sites. And, mostly on sitepoint. One thing you must do is make the buyers contact you first before placing a bid on your auction. I recently dealt with some fake buyers, not only one but two on sitepoint.
Also, people love stats. Traffic stats, revenue stats, etc etc. So, stats are a must have for any auction.
There are some other auction places too, I do not want to advertise any on this thread.
Linda/Larwee - I have been away for quiet sometime. But, I am back now
