I've been doing AdSense and AdWords since 2002. I used to spend as much as I made to drive traffic to my products without net cost. It has been a constant fight over the years to keep my ads in a good position . . . had to go to 37 discret sites to be sure that the most important keywords had sufficient presence in the site pages. When all were combined on a single page, I couldn't get decent rankings for any.

Also, Google has refused my best ads . . . I make software for investors that help them invest in Fidelity and Vanguard mutual funds . . . that worked fine until Google decided that there was no such thing as fair use of trade marks. Even a letter from Fidelity saying that my use of "Fidelity" did not violate their marks was worthless . . . Ads I tried to change got refused and required special appeal. Also, random Google scans would cancel ads even if they weren't changed and even if thay had been successfully appealed previously.

Through all this, my Google adSense revenues a have varied from $1,000-$700/month . . . improving over the past month. At one point in late 2002, I was up to $3000/month, but then Google made changes that cut me back to currentl levels. Since mid2003, I haven't seen a lot of difference in my adSense revenues.