So we know Google is seriously testing AJAX search results and Google has confirmed that. We know Google was not passing referrer strings to the receiving sites, but Google promised to fix that. But these changes are going to be coming to a Google search result near you, so you need to be aware of it.
Matt Cutts of Google posted a video explaining a bit more about these changes. It is well worth watching the 3-minute video:
Forum discussion continued at WebmasterWorld.

Comments:
Pattrick Lewis
05/07/2009 02:04 pm
What does Matt mean when he says that this only affects a small percentage of users right now? I just don't get that.
Matt Cutts
05/07/2009 02:13 pm
Pattrick, that means that the vast majority of users are still seeing the regular search results, not the Javscript-Enhanced Search Results.
Adam
05/07/2009 04:03 pm
So where will we see these results? Is this going to be the url in the browser, or will this be what we see in our analytics reports?