They were served up in some pretty high-trafficked areas too, like Zoominfo, AOL/Userplane, and Belief.net. Rubicon says it works with 13 sites that generate 100 million impressions per month.

That’s decent exposure for the 2000-plus websites that signed up for the private beta.

"Things are moving at lightning pace at the Rubicon Project, as we’re busy building and testing a solution that will bring a new level of efficiency to the fragmented Internet advertising space," said Rubicon CEO Frank Addante, in a statement.

"Although we’re trying to solve a very big industry problem, our initial results and feedback from sites currently part of our beta — the development phase where it is essential we get things right — are extremely encouraging. Everything has gone smoother than expected, and we head into 2008 with great excitement and aggressive plans to revolutionize the industry and become the online advertising standard."

Rubicon’s got a decent pedigree. In 1998, the company also created L90/adMonitor, an advertising platform said to have reached nearly two-thirds of the Internet population before DoubleClick acquired it. That means Google owns it now, pending European regulatory approval.