Unless you've been living under a rock, you know how auction-based media works. Just in case you have been living there, let's recap, shall we?
In search marketing, Overture is a pure auction-based advertising medium, while Google uses a combination of bidding-plus-relevancy to deliver your message. Both companies charge based on the click. So, the more you're willing to spend to reach someone looking for a specifc search term, the better the placement of your ad.
Well, there's a new network in town. (Literally. Right here in NYC.)
Right Media is a sophisticated advertising network founded and run by a group of former DoubleClickers. Their proprietary software automatically optimizes your campaign based not only on the audience you're trying to reach and the performance of your campaign, but also on the maximum you're willing to pay to reach that audience.
Each time an ad call is made to their ad server, the system reviews the bids that each advertiser has pledged for that particular audience, then serves the appropriate ad. (Note: this is not keyword based.)
Any marketer who needs to back into a specific CPA will immediately understand the benefits here. For a better understanding of their methodology, take a look at this network comparison chart, then check out the rest of their web site.
I'm running a test campaign with them for a client and I expect the results to be in line with the target CPA. While I can't disclose actual numbers or other details, I'll share my overall perceptions.