We forwarded our SEM clients a whitepaper we put together last month about the change in the way Google displays keyword data in Google Analytics for those users who are logged into Google while performing a search (they show as "Not provided"). Though we didn't know it at the time, the change may have been made by Google to prepare for this rollout. The keyword information for these logged-in users needs to stay private, as people are going to be doing more private searches now that they can access both their private and public information at the same time through their Google searches.
While we continue to do research to find the SEO changes associated with this rollout, we urge you to set up your Google+ page if you haven't already (http://www.google.com/+/business/) and consider adding the Google+ button to your website.
Find more information about "Search, plus Your World" here: http://googleblog.blogspot.com/2012/01/search-plus-your-world.html.