Since Facebook is a global phenomenon and more and more people use it to spread and share information around, and because Facebook just recently introduced their 'LIKE' API feature that just makes sharing even better.. We just got it incorporated around the forums as well!
I believe the rest is self-explanatory, as whatever you 'Like' is shown on your Facebook Wall and your friends' newsfeeds.
Please wait a moment after your name appears beside the Like button after you hit it. Check for any Error message for a couple of seconds, if it isn't displayed then your Like was successful, or hit Like again. This issue happens occasionally. You might also want to check your Facebook Wall if the Like was displayed.
Soon: 'Share' buttons for Facebook, Twitter, etc.