Cubics.com, a Facebook application ad network, was acquired by Adknowledge on November 30th. An email notifying Cubics.com publishers went out earlier today. Adknowledge os the owner of BidSystem.com, “a multi-channel behavioral targeting ad network in which advertisers seemlessly bid for traffic in display, email and smaller search engines.”

While I personally haven’t heard of Adknowledge, BidSystem has been used by over 50,000 advertisers. No information has been provided about the amount Cubics.com was acquired for. With all of these smaller ad networks on Facebook, I wouldn’t be surprised if we continued to see consolitdation as larger ad networks enter this space.

RockYou, Social Media and now Federated Media each have dominant positions but there are a handful of smaller ad networks. The majority of the ad networks have been selling inventory to other Facebook application developers. As such, many have described the current environment as unsustainable. I agree.