I think this is a really sneaky, back door attempt to keep SE's in business and has nothing to do with "usability".
And just what is more 'usable' than something that allows one to stay in business?
Duck and snicker.I see it as a potential filter, a method of refining the quality of click throughs, which would also allow an increase in rates - although they might use the G model and rather than exclude 'less usable' ad space charge the crap more or pay out less.
...when people HATE ads?
* Do people buy
Vogue magazine for the thin content or the luscious display ads?
* What is
O but Oprah's print ad server ala Google.
* Why do so many 'good' or 'bad' ads get uploaded to YouTube?
Advertising done properly is appreciated:
* for itself as an art form.
* for the emotion, especially humour.
* for the product/brand (and to a lesser extend the artist/agency/creator).
* for the revenue generated and audience acquired.
There are very effective quite attractive ad (conversion) funnels out there. That they are still few (thanks to the proliferation of AdSense, clones, and lazy domain devs) means they are that much more effective.
It likely means even more heartache among the add-script-and-wait and the ppc-landing-page crowds, though.

As for your RANT - don't hold back, don't let it fester, let it out and ROAR!!!
I am woman, hear me roar...
There is nothing that releaves stress and aids a healthy heart like a good RANT and ROAR.
Mens sana in corpore sano