Maybe you're not a geek like me. Maybe you don't know what HTTP or HTTPS stands for, or what the difference is.
But chances are, you use Facebook just like millions of others. What you do need to know is that because so many people use Facebook, and post so much personal info on the site, it's become a prime target for hackers.
In a move resembling something of responsibility (odd for Facebook), the company has made their site available to be browsed over a secure HTTP link .. also known as HTTPS.
Once setup, the only difference you should notice is that the address in your web browser should look something like this:
Notice the "HTTPS" instead of "HTTP". For starters, you should make sure that any bookmarks or shortcuts you have that link to Facebook have the HTTPS instead of HTTP. In addition, the site also has an overall account setting, that will try to make sure your link to Facebook is over HTTPS whenever possible.
To do this, go to your Account Settings page and look under "Account Security". There's a check box setting for "Secure Browsing (https)". Enable it and save it. Now, whenever you connect to Facebook on your account, it will direct you to a secure link.
The original post with all the details can be found on the official Facebook Blog here.
Now, go forth, and get paranoid!