If you are one of the close to billion users of Facebook then there is one simple thing you should be doing when you visit the website or use the app on your device.. SIGN OUT when you are leaving the website.
You should be treating this website just like you would your online banking or credit card website. You sign out/log out when you are through. If you have a banking app on your phone you will notice when you swap pages and come back to your banking app it has likely automatically signed you out but if it hasn't then you should be making sure you do sign out before going to other apps. This is the same for facebook. When you want to share something to facebook it will prompt you to sign in to your facebook. Go ahead and do this but be sure the checkbox that displays "stay signed in" is NOT selected.
The problem with staying signed in is the app continues to track you and monitor your activities. This includes the web page version as it will continue to use the cookies to track. The other problem with Facebook web page sign in is there are so many other plug-ins and scripts that run, depending on what you have allowed to run within your facebook window so simply closing the page means those apps are still running in the background.
I realize it is one more step you have to take but isn't your internet security worth it?
