Receptional_Andy - 1:49 pm on Feb 5, 2009 (gmt 0)

Google have always been a fan of large scale live tests. Certainly this is large-scale enough to make it much less likely that it's not going to go any further.

coop: got it. The AJAX request is for exactly the same results page (via GET) that would be triggered prior to this test. Then the whole page content is pretty much replaced. So internally at Google, it's pretty much the same as before. Very smart!