When I first found this out, I was shocked. By default, Firefox gives users the ability to view a list of all your saved usernames and passwords, as well as the sites they’re associated with. Check it out for yourself by going to Tools > Options… > Security > Saved Passwords.

Not a good thing. What if someone jumped onto my computer when I forget to lock it? They’ll find out that my passwords are cooldude, password, and ilikepink, which will be really embarrassing. Luckily, there’s an easy fix. Go to Tools > Options… > Security, check the “Use a master password” box and set a (strong) password. Periodically, and whenever you startup the browser, you’ll be asked for this password. Without it, prying eyes won’t be able to see your password list or automatically login to Facebook and pretend to be you.