We are using Flippa now for Auctioning Domains
On domain forums, where posting is free, there are so many posts of low-quality domains that the sites are barely useful anymore. But with Flippa, you have to pay $9 to list a domain for sale (and it can go much higher if you use their marketing options). Many domains sellers have done with with Flippa.
Our current auctions are for Lithogaphy.net (with a partner), Sinaloa.net, and ComputerLanguages.org.
You can see all of our Flippa auctions here.