Gmail announced the always-secure feature last year, and now Facebook has finally got around to adding it as well.
This account feature will allow users to use https whenever possible, making it a more secure experience.
You can access this feature by going Account » Account Settings » Browse Facebook on a secure connection (https) whenever possible
The Firefox extension Firesheep, has brought to light many concerns about security on social networks such as Twitter. It’s great to see Facebook being proactive about making the experience more secure.