Will This Be The New Google Web Design?
sixrevisions.com
sixrevisions.com
On my netbook it hid the sidebar (I think this was deliberate and not a split)
I've also had it appearing/disappearing by default on various desktop machines (I think that was a split).
I have to confess it is growing on my as a feature. The icons convinced me to start using the filters and some of them are useful.
After edit: for the rest of you who have seen this feature of the left side tools, have any of you been served up an option to turn it off?
Obviously, that's what they are interested in, in the long run-- but to test design changes, they need a more specific (and easily measurable) metric. And, no doubt, they have one. I just don't know what it might be.
To answer your question, if I was to pick up only one, the first that came to my mind was "pageviews". So, everything that increases pageviews is good. Well, not quite, because so is CTR, and in fact doubling CTR allows you to halve pageviews.
Anyway, whatever they think of, the ultimate step is money earned. No single path leads to this, but several, like pageviews, CTR, click value, searches per day, other services integration, etc...
Edited: You're thinking about A/B testing but I don't know if you're aware there's also multivariate testing, which Google does use (its optimizer easily creates A/B and multivariate).
Anyway, it's confusing that the very first image, directly below the title, shows a search box that is tilted wrt its background. Now that would be innovate design... :-)
All this "looks more modern", "provides more consistency" claims are subjective, sure, but if enough people think like this it's already a win for Google.
First impressions: "nicer" to look at for the most part - but no more or less functional (fresh is, I think, the best word for it). The sidebar is initially disconcerting/nasty but it's growing on me quickly.
Including something resembling the '80 million dollars blue'.
Split testing is awesome.