"In the past month, Google quietly made a change aimed at encrypting all search activity — except for clicks on ads. Google says this has been done to provide 'extra protection' for searchers," reports Danny Sullivan.
For example, if you type google.com in your browser's address bar, you'll be redirected to https://www.google.com. "SSL encrypts the communication channel between Google and a searcher's computer. When search traffic is encrypted, it can't easily be decoded by third parties between a searcher's computer and Google's servers," informs Google.
Danny Sullivan speculates that this move may be aiming to block NSA spying activity, but I don't think that's the case. Google still logs all the search traffic and it can send that information to the authorities.
A major downside of switching to encrypted searches is that webmasters can no longer obtain a list of the Google search keywords that sent traffic to their sites without relying on Google services. Google Webmaster Tools includes a list of keywords, but this feature is limited and doesn't integrate with analytics software. There's an exception: ads. "Ad search traffic has never been made secure. No encryption stops people from eavesdropping on the terms used when someone searches at Google and clicks on an ad. Google's also never prevented this information from flowing directly to advertisers, in the way it has for non-advertisers," says Danny Sullivan.