Flippa has certainly ramped up its domain only auctions since Kevin Fink came on board and jump started things there.
There is a special promo running good for one week, that he just released,
From now through month’s end, when you list a domain on Flippa, you’ll be given a special link to redeem 1 FREE Domain listing!
Here’s how it works: go and sell any domain name. When you pay for your first listing, you’ll receive — in your listing confirmation email — a special link. Click on that, and you’re taken to a spot where you’ll receive your 9 credits — enough to apply towards an upgrade, or list / relist another domain name for FREE.
The only restrictions are that this is limited to one per account, and will expire August 1st at 12:01am, PST. Oh, and…domain listings only — you cannot apply this to websites or apps.
So if you are thinking of running an auction, now is the time.