Sounds absurd but this kind of application can be useful too.
An app that can automatically log you out from Facebook after certain time may not be something you'll use everyday. But just in case you're on a shared computer and you don't want others to mess around with your account, this category of app is proved useful.
Facebook Auto Log Out: Automatically Logs You Out From Facebook After User-Specified Time (link)
Meet Facebook Auto Log Out, a nifty Chrome extension designed to do just that. Using the add-on is pretty straightforward; just install the add-on from Chrome Web Store, log in to Facebook, set a timer, and you'll be logged out automatically when your time is up. It's that simple
This is particularly helpful for people who have this hobby of leaving the computer opened/unattended. Auto Logout. It automatically logs you out of all logged in accounts including Gmail when your browser is closed, recommended for use in shared computers to help keep different accounts safe.