YieldBuild is an advertising optimization system that works with several major ad networks to provide the best possible ads - based on performance - for your website. They have just announced that a previous 3 percent fee to optimize ads has been dropped.
Some of the networks included are Google AdSense, Yahoo! Publisher Network, Tribal Fusion and Blue Lithium. YieldBuild also recently partnered with Microsoft pubCenter. After signing up, publishers choose the sections of their site where they would like to display ads. YieldBuild then provides one snippet of code to install and starts delivering ads. The ads are then tracked and monitored (publishers also get a suite of analytics tools), and the best performing ads are delivered to users. Some of the ways ads are optimized include color, size, format and positioning. And even though the system uses a mix of ad networks, publishers can still monitor ad performance through their existing accounts with those systems, and they still get paid through their current provider.
For the busy Web professional it's not a bad way to see if you could be getting more from your current ad space.