Google Encrypted Search
Google encrypted search is very important to internet marketers, it makes reporting on organic search traffic more complicated.
From Google:
"What does this mean for sites that receive clicks from Google search results? When you search from https://www.google.com, websites you visit from our organic search listings will still know that you came from Google, but won't receive information about each individual query. They can also receive an aggregated list of the top 1,000 search queries that drove traffic to their site for each of the past 30 days through Google Webmaster Tools. This information helps webmasters keep more accurate statistics about their user traffic. If you choose to click on an ad appearing on our search results page, your browser will continue to send the relevant query over the network to enable advertisers to measure the effectiveness of their campaigns and to improve the ads and offers they present to you."
Official Blog Post from Google