MikeNoLastName - 8:23 pm on Jun 14, 2007 (gmt 0)

I've heard many people report that Thurs seems to be algo-change-day or Smart-pricing-takes-effect-day whichever you believe in. Personally ours usually seems to switch on Saturdays.

We've been getting the duplicate ads for almost a year, and we told G then, (especially since it used to be somewhere in the TOS that you sould not display identical ads on the same page, and THEY were causing it) but to no avail. It seemed to start when we started using google-ad-region. I'm guessing you're using it too. We just started removing the extra ad blocks since they were obviously redundant and seldom got any additional clicks.

I had one interesting observation the last couple days. Our earnings have been down since Feb right around the time we started noticing something new. Seemed that ads on all pages account-wide or at least site-wide were leaning towards two particular sub-topics. These two topics were those, which in our channel level reports had the overall highest CPM compared to other pages, but are in a relatively narrow topic which does not necessarily appeal to most of the rest of our site. However while the ads did very well CPM-wise, by virtue of either high CTR or high PPC, ON the pages where they were APPROPRIATE, they did NOT do so well on the rest of the site. Since they were not applicable to the other pages, they tended not to get clicked. More of them were of the lower PPC variety, so even when they were clicked, they tended to lower the overal CPM of the pages they were now on inappropriately.
For example, say the site was about all different power tools (our actual case couldn't be further from that topic), with a single page on various jackhammer bits, and another single page on electric screwdrivers. Ads for electric screwdrivers get a nice 35% CTR on their page and jackhammer bits get a lower CTR but since they have a much higher PPC still get a very nice CPM for on their page. The electric screwdriver page, in this example, is our most popular entry point and a #1 for it's keyword phrase on G, but has a relatively low PPC of only .10. But, becasue of the high CTR we wind up with a hefty $35.00 CPM there. The jackhammer bits page is relatively low traffic, but has a decent CTR and a very nice $1.50 PPC, so it winds up with probably a CPM of $85.00. Yet when those same ads start bombarding the radial saw pages, the electric drill pages and even the precision lathe pages, they get relatively no interest and the CPM on those pages has dropped below $2.00 due to the much lower average CTR. Our overall CPM, PPC and Overall earnings dropped to about 1/2.

Then just the other day I decided to try removing the ads just from those two offending pages, totally. It only took about 12 hours and suddenly all the ads went back to the way they used to be a year ago in happier times and our CPM and PPC skyrocketed almost back to the previous levels! I've replaced the ads now (they were rather lucrative in themselves) to see what happens.

I'm begining to think there has been a new flawed algorithm added with good intentions, but bad results, that is doing this and is causing a lot of advertisers earnings to fall. Perhaps it works very well for some types of sites (perhaps ones where the entire site is very focused and ads are interchangable across all topics), but not for slightly more diverse sites like ours, where visitors viewing one part of the site are not interested in ads from another part!