Google has changed its procedures to enable "forward secrecy" by default on all its search-traffic. This means that part of the key needed to decrypt the traffic is never stored, so that in the event that there is a security breach at Google, older, intercepted traffic can't be descrambled. It's the absolute best practice for secure communications, and Google is to be commended for adopting it.
Other web sites have implemented HTTPS with forward secrecy before — we have it enabled by default on https://www.eff.org/ — but it hasn't yet been rolled out on a site of Google's scale. Some sites have publicly resisted implementing forward secrecy because it is more CPU intensive than standard HTTP or HTTPS. In order to address that problem, Google made improvements to the open source OpenSSL library, and has incorporated those changes into the library for anybody to use.
Forward secrecy is an important step forward for web privacy, and we encourage sites, big and small, to follow Google's lead in enabling it!