buckworks - 8:24 pm on Sep 3, 2012 (gmt 0)
no call to action, no product offered, and in some cases there is no text merely a photo or a graphic with the logo.
Those are not necessarily signals of CPM, but they are definitely signals of a clueless advertiser.
The belly fat ads could be either CPC or CPM, but either way the reason they show up is that they're either outbidding or outperforming whatever other ads the algo might be considering for that page at that moment.
not sufficiently well "focused" to pull in subject related ads
If, indeed, there are any subject-related ads available at that moment.
For publishers, the notion of making sure our pages are well focused is vital, absolutely vital. Assuming that subject-related ads are in fact available, we'll have a better chance to get them if the algos can tell without a doubt what the page is about.