As they roll it out, people signed into Google accounts will find themselves redirected to an SSL encrypted page for searching by default. If you are not logged into a Google account, you will still be able to access their secure search by typing https://www.google.com into your browser's address field.
Make sure you include 'www' in the address or else it will send you to the normal (unencrypted) Google search.
This is intended primarily as a measure for people using unsecured Internet connections, such as public Wi-Fi, where your communications are particularly susceptible to being intercepted without your knowlege.
However, it will also affect what information is available to websites you visit via Google searches.
According to Evelyn Kao, product manager at Google:
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.
Written by: Rich Fiscus @ 19 Oct 2011 6:02