At the moment Google is using the USA as a testing ground for the delivery of searchresults through Ajax (not the cleaning-agent but the JavaScript-Voodoo). While this may have advantages for some users because the whole page does not need to be refreshed when scrolling through the results, there are also a number of disadvantages which are already hotly discussed in US-blogs (via Seofm). As far as the first point is concerned, I do not think it to be so critical: it makes no difference if Rankingcheckers parse the (regular) HTML-SERPs or some serialized JavaScript-data. Sure it will take some time to make the switch but in principle this is no problem – it is possible that both sides might even save some traffic ...

The second point of criticism is already more critical which is due to how Ajax delivers parameters. First off the regular SERPs, each time for a search for “sistrix”:


The browser will (usually) deliver the full URL including the parameters as referrer and this information will also show up in the webserver-logfiles where it can be evaluated. This looks somewhat different for the Ajax-integration:


The searched for keywords are written in Google's HTML-anchor. Seeing how these are informations that are usually only needed by the browser to jump to a specific region of the site, it is not being transmitted in the referrer. This means that the webserver-logfiles as well as any other method of analysis will only receive the part before the “#” which does not hold any hints about the searched keyword.

Should Google decide that the current tests are successful and should Ajax-SERPs become the norm for all Googlesearches, then there will be a huge problem for every analysis-tool and -possibility and, at the moment, I can not see a way how the keywordinformations could still be attained with the current Ajax-implementation. Matt Cutts is admittedly giving the all-clear in the linked blogposting (“It is not our intention to disrupt referrer tracking, and we are continuing to iterate on this project.“) it will still be thrilling to see if and how this change will come along.