A new feature of Firefox 17 is its new Social API which allows you to integrate Facebook into the browser. This means that if you are logged into Facebook you will be able to see your friends, read your news feeds and receive notification. You can also chat with your friends using the Facebook Messenger on all websites you browse. Here is how to enable it.
Make sure you are running Firefox 17 by checking your version in About Firefox.
Next open https://www.facebook.com/about/messenger-for-firefox. Click the Turn On button and login to your Facebook account.
That's it, now a few Facebook icons will appear at the menu bar as well as a sidebar with your Facebook friends.
To remove it click the Facebook icon and select Remove from Firefox.
Twitter is said to be the next website that will be integrated with Social API.
What do you think about this service?