Gabtastik

Gabtastik is a Site Specific Browser (SSB) for web chat services, designed to let you easily connect to your Facebook and Gmail accounts from a desktop client. It sports just a couple of intuitive options that should be easy to figure out by anyone.

Clean and intuitive desktop client

After a brief and uneventful setup procedure, you are welcomed by a user-friendly interface, represented by a plain-looking window with a simple layout, where you can get started by selecting the web service to connect to: Facebook or Gmail.
Once you've entered your login credentials, you can access your account and carry on with your normal session just like when using the traditional method via web browsing.

Systray accessibility and app customization

By default, Gabtastik creates an icon in the system tray area and gets sent there on close. It becomes non-intrusive this way, enabling you to focus on other PC activities and quickly open Facebook or Gmail whenever you need to. More importantly, it shows notifications when new messages arrive.
As far as options are concerned, it's possible to refresh all information from the status bar, seamlessly log out to log in with different credentials or to switch to another online service, print data, make the main app window stay on top of other frames, adjust its opacity level, hide the systray icon, disable the notifications, or activate script debugging on launch.

Evaluation and conclusion

The application didn't put a strain on the overall performance of the machine in our tests, thanks to the fact that it needed low CPU and RAM to work properly. However, the Google service doesn't seem to be working anymore, and Gabtastik prompted some error dialogs when we were tinkering with some of its options (e.g. checking for software updates).
On the other hand, we should take into account that it hasn't been updated for a long time, and the project is likely discontinued. Nevertheless, you can test Gabtastik for yourself (it works fine for Facebook).