bbcarter - 7:34 am on Apr 12, 2005 (gmt 0)

I sent AdSense another email about my odd declining impressions % - got a form email back about CPM etc. (even tho I was concerned about clickthru, not CPM- evidently that's been a concern for others)- thought you might be interested (below)-

and btw I'm becoming quite certain I need a mix of revenue sources, just like you need a mix of traffic sources... because AdSense seems to have NoSense ;-)

Hello,

Thank you for your email. I understand you are concerned with a decrease
in the effective CPM associated with the Google ads you're serving through
AdSense.

We're constantly analyzing data across our network against a variety of
factors. If our data shows that a click is less likely to turn into
business results (e.g. online sale, registration, phone call, or
newsletter sign up), we reduce the price that an advertiser will pay for
that click.

We take into account many factors such as what keywords or concepts
triggered the ad as well as the type of site on which the ad was served.
For example, a click on an ad for digital cameras on a web page about
photography tips may be worth less than a click on the same ad appearing
next to a review of digital cameras.

Please also understand that your earnings will depend on a significant
number of factors, such as your users' clickthrough selections, advertiser
spending campaign trends, and the types of ads being served to your pages.

At the same time, we're improving the targeting to content pages, to show
ads that are even more relevant than before. Even when a page contains
multiple topics, we'll be able to know which topic is more relevant to
your users. As a result, you'll notice an increase in your clickthrough
rate.

These two improvements to our advertising program are intended to increase
the long-term revenue potential of AdSense publishers, by driving rapid
growth to our advertiser base, and by providing more relevant ads and a
better user experience. Your AdSense reports will give you a good idea of
the effect of these changes over time.

I also understand that your clickthrough rate has dropped as well. As our
advertiser base is constantly changing, different ads will appear. I
reviewed your site and it appears to be showing relevant ads at this time.
Your users may also be affected by ad blindness. To decrease ad blindness,
you may want to rotate your color palettes to keep the ad appearance fresh
to repeat visitors.

Please feel free to reply to this email if I can be of any further
assistance.

Sincerely,

The Google AdSense Team