Google to Change HTTP Referrer
From April 2012 you can expect to see faster click through from Google search results as the search engine switches to the “referrer” meta tag to handle the referring URL from organic search results. The feature will be available only in browsers which support it (e.g. Chrome) .
Webmaster will start seeing Google homepage as origin referrer and source of organic traffic via SSL.
No reason for concern though, the change won’t increase the number of (not provided) keywords as it affects a portion of SSL search traffic which hides the search terms regardless. Non-HTTPS traffic remains the same.
In analytics we’ll be seeing these searches as organic and under Google’s own domain, for example: https://www.google.com.au/.
The aggregated search query data will be visible from Google Webmaster Tools as usual.
Could this be somehow related to a case of inflated organic traffic  we reported on earlier?
 Upcoming changes in Google’s HTTP Referrer
 The Case of Inflated (not provided) in Google Analytics