[google.com...]
Dec 2004: Link to pure PPC appears at end of PPC links.
Mar 2005: Link to pure PPC appears on more prominent places.
Jun 2005: Natural results moved to the right and PPC on left.
Sep 2005: No natural results for commercial KWs, With a link to 'non sponsored' at the bottom.
Dec 2005: Only pure PPC results for commercial KWs.
Mar 2006: All the other major SEs do the same.
Their whole value proposition is their ability to out search the other engines.
With the bundling capabilities of Yahoo and MSN, I can see them wanting to do something like that because they can force you into their search engine other ways.
Google however, doesn't really have anything to force people anywhere except the genius of their search.
Also, I'd change your methodology. I think more results at the top of the page slowly pushing natural SERPS further and further below the fold will be the tactic of choice.
In fact, over the years, there has been improvement (thanks mainly to Google) in the way that paid/non-paid results are displayed in the serps.
Your timeline assumes that SE's can and will draw visitors to pure-ppc results. Ask yourself: how many people use Overture to search?
Heck, Overture themselves started off as a consumer oriented service (GoTo), before they figured it out and re-branded as a B2B outfit.
I look at it the same way that I look at my own sites. Yes, I strive to maximize the number of clicks that I can send to my affiliate partners, but at the same time, I can't overdo it, I HAVE to publish quality content, otherwise no one will have a reason to visit.
Same goes for Google et al. If they don't provide quality spidered serps, then no one will use them for search, and they will not be able to display their fancy ads to anyone at all.
Where's AWA!
I was hanging with the family in the Land-of-No-Internet! (Mom's house, in other words.) Glad to know that my absense was noted, however. ;)
As most of you know from having watched for a long while, Google tends to test a lot of things - and I imagine this is one such case. I'm actually not aware of the nuts and bolts details, although I'm sure that if this were to become a 'feature', then documentation in the FAQ would come along with it. ;)
AWA
An amazing transformation in my mind:
My friends / colleagues mention google as G:
Till October 2004: Connotation -> Great
October-December -> Materalization of a transformation.
December 2004: Connotation -> Gone.