On October, 18, 2011, Google announced they would be encrypting search queries, for privacy reasons. Unfortunately, this disruptes organic keyword referral data, returning “(not provided)” for some organic traffic.
Before this change, Sites could both see that the visitor came from google.com and their search query. However, for organic search results (i.e. non paid) on during a SSL search, a web site will only know that the user came from google.com.” The effect is an increase in the number of searches showing “(not provided)” as the keywords. Clearly, the inbound marketing community isn’t thrilled.
Read more on Google’s statement on the change to Make searches more secure