Google Analytics product is no longer identifying the exact keywords used for organic when someone is signed into google. This affects a very minute portion of searches. Traffic will still be reported, however...there is a slightly lower "pool" of data that they are pulling the organic search term information from. It should not skew organic traffic data counts and the data still should, in theory act perfect as proxy. More info on Google Analytics Blog - http://analytics.blogspot.com/2011/10/making-search-more-secure-accessing.html