Facebook has a chat feature which I use to chat with some of my friends who are usually not available on IM, however everytime I want to chat with someone I need to go and open the browser to chat.
Gabtastik is a site specific browser (SSB) based on Webkit (remember Mozilla Prism) that will allow you to chat with your Facebook friends from your desktop without having to open a web browser.
Once you install the software you can start using it to communicate with friends, all your chat sessions are can also be viewed when you visit the Facebook site.
Gabtastik also provides you with non intrusive chat notifications whenever someone opens up a chat with you by showing a balloon notification in the taskbar whenever someone chats with you or replies to you, so you can open the application and keep it running without having to visit your Facebook profile to check for chat notifications.
A bonus with this application is that it also can also be used as a desktop application for Google Talk.
Overall simply awesome, even if you don’t use Facebook much, this is a definite must have to Google Talk users.
Gabtastik is available for both Windows and Mac OS X.