I worked in retail for some time where people would come into the store to use the computers to check Facebook, Twitter, or even their email. That was totally fine, because we wanted them to get a feel for the products they would hopefully purchase. The problem was that they would forget to log off from these sites when they were done. So here's the scenario:
Jessie comes into the store and logs on to FB and posts on the walls of her friends and even uses the camera to upload a picture. She then leaves the store forgetting to log off. Tony walks in and wants to check his email. When he gets to the computer he sees that Jessie is still logged on. Tony, a bit of a trouble maker, decides to have some fun and teach Jessie a lesson. He posts on Jessie's friend's walls cursing them out and making up stories about them, trying to stir up trouble.
Jessie gets back home and logs into FB and sees everything that Tony has done. She's left with a big mess, a lot of apologizing and explaining to do. Jessie calls the store and gets their help in logging off but the damage is done. While everything Tony did is crazy, what's even crazier is that Jessie is upset that stores didn't log off for her after she left! Listen, stores and other people are not responsible for making sure you log off a website. That's your job, your responsibility. And in this case, Jessie's responsibility.
If someone starts posting offensive messages on your FB wall, do you really want to have to explain to people that it wasn't you? And do you really want to explain to your friends and family how someone got access to their personal information, because once a stranger is on your FB or email, they can see all of your contacts? Yikes!
And this isn't limited to stores or public places. Even if you're at a friend's house, you might want to log off or be the victim of a prank.
Easiest solution = Log off or don't log in in the first place. 🙂
Just some food for thought.
You ought to know: Logoff websites and social networks. You are responsible for anything that happens while logged on.