Who is using OpenX as a backend of an ad network?

Is there a company which use OpenX as a solution for an ad network? (pay per click or/and CPM)
I recently reviewed OpenX ad server (which is free and open source) and I’m curious if a company is using it for building an ad network for publishers and advertisers (like Doubleclick, Adbrite, ValueClick)…not just for their individual needs.

See original post by mg1313