Because caps lock changes the input of the letters on the keyboard, it is important to know whether it is on or off. Therefore, most keyboards have a light on the caps lock key that turns on when active, indicating caps lock is on. Because passwords are often case-sensitive, it is smart to make sure caps lock is not active when entering login information. Also, it is best not to use caps lock when typing e-mails because IT MAKES IT SEEM LIKE YOU ARE YELLING when you type in all caps.