Scott,
We haven't tried turning off Adsense - but here is an alternative
theory to your results:
Google has to get all advertisers onto a common contract while
delivering ads on a common platform. Until all the contracts are
transitioned, and all the ads also, there will be problems with ad
categories, publisher categories and ad selection/filtering
algorithms. The old "AdMob" ads will disappear along with the old
"Adsense" ads, while they become one common group. Adsense "back fill"
allows delivery of Adsense ads to the Admob platform during the
transition. Once the advertiser transition is done (and advertiser
contracts are revised and signed) it won't be "back fill" anymore - it
will just be the "regular fill" or standard ad inventory.
That said, I'm glad you checked it out because it could have gone the
other way, for some reason. However, since it didn't go another way,
it still leaves a lot of questions.
What will the new publisher contract and tool set look like? Will they
change the filter mechanism and what will the capabilities be? Will we
be able to adjust ad category fill rates? (Turning categories on/off
only is like trying to fill a bathtub to the right temperature and
"Hot" or "Cold" are either on or off, no middle ground. Unless having
both "on" is the perfect mix, you have to constantly adjust by turning
them on and off. For example, I think Personals would work very well
in some of our apps, but when I turn it "on," then virtually all ads
are personals and it saturates the audience; when it's off, I get a
lot of Adsense ads, many of which are not relevant.)
Our most important tool, as developers, is the ability to filter ads
that are appropriate to our audience. As Adsense back fill becomes a
larger portion of ads (or the entire inventory), and as "AdMob" ads
decrease, available AdMob ads will saturate our users until the
inventory runs low, then we get unfiltered "Adsense" ads. So we should
expect inconsistent revenue and results (we will notice lower revenue
more easily) because overexposure occurs, followed by random ads. I'm
sure they are working on the tools, but like all things in life, it
can't get here fast enough.
-Jim
As an aside, it would be nice, for publishers, to have Adsense
advertisers transition to the "old" AdMob. And maybe they are
integrating new ad contracts into "old" AdMob ad inventory, but I do
not see support for that theory. They need a new, consolidated
publisher contract. In other words, Adsense advertisers cannot be
expected to automatically accept the old AdMob rules, or vice versa.
They need new contracts in order to move forward.