People are always comparing their old Google Adsense numbers with new ones. If the CPM is down, they’re likely to complain. But you have to take a few factors into account before you automatically assume you’re a victim of a conspiracy theory. Adsense is only as good as the traffic you drive to your website, and if you traffic profile changes, so will the CPM.

Keyword values have a tendency to erode

Advertisers are always looking for ways to pay less for keyword ads, and webmasters who publish the ads always want more. This puts the two parties at odds, in a way. When you get used to a certain payment for your ads, you get a little upset when you see the CPM erode. Maybe you even blame Google, thinking it would help to explain their soaring stock price. But before you waste too much time muddling around in negativity, consider the idea that it might just be that the advertising mix that used to exist is gone, or your traffic has gravitated towards lower paying keywords.

I add content all the time, so it’s possible I’m driving lower paying traffic to my websites. It’s a chance I’m willing to take in order to enjoy the benefits of higher traffic. To me, higher traffic is higher earnings, even if you have a downward effect on CPM. Plus, gaining more traffic through adding content is a factor I can control, unlike so many others. So I add content, and I tend to see a slight downward trend over time as it relates to CPM, but not total earnings. I can live with that.

In the end, the best way to avert a downward CPM spiral is to keep on building some higher value CPM keyword pages along with your news-driven and lower paying keywords. If you add enough of them, you can stem the bleeding as it relates to your CPM.