What were the content sites that AdWords ran on before AdSense came along? On another forum, the names that I saw mentioned were HowStuffWorks, Knight Ridder Digital, BURST! Media, Weather Underground, and Google Groups. It's pretty easy to understand why those sites might not generate good ROI:
- A person looking at a page on digital-camera technology at HowStuffWorks isn't likely to be as good a sales prospect as a person who's reading a review of the Canon PowerShot S50 at Steve's Digicams or DPReview.
- A person checking a forecast at Weather Underground isn't likely to be in the market for anything, unless he's trying to decide when to buy an umbrella or a snowblower.
- Forums (of which Google Groups would be an example) have never been known for being high-quality ad media. Even when big-name Web sites were charging high CPMs for editorial or search pages, forum and chat views were going for a relative pittance.
IMHO, those early Google "content site" partners weren't the best venues for highly targeted ads like AdWords, and that's why they performed poorly. With AdSense, "content site" AdWords should be on much more targeted pages and sites than they were in the pre-AdSense days. To use a hypothetical example, an AdWord for "20% Off Tumi Luggage" in a travel site's article on "packing for your honeymoon" could be very effective. It certainly should have a higher ROI than the same AdWord on a HowStuffWorks page about airline luggage-handling systems. :-)