Google released a whitepaper titled "CPA Performance Trends on the Google Content Network." The whitepaper has the following findings, all very positive about how Google AdSense performs:
- Ads on the Google Content Network are likely to be as cost-effective - or even more cost-effective - than ads on the search network.
- The median advertiser has a content CPA that's about 2% lower than their search CPA.
- The Content Network drives a significant share of total conversions.
- The Content Network drives nearly 20% of total conversions for the median advertiser.
- Conversion rates are higher for advertisers who used either of two AdWords campaign management controls: the Conversion Optimizer and site exclusion.
Thing is, no one believes the report. A WebmasterWorld thread has real advertisers saying they don't see this in their daily use of Google's content network and this seems to be a Google backed study that would bias the results.
Forum discussion at WebmasterWorld.