This is interesting in facebook password. You can log into your Facebook account using three passwords one is the main password that you have create and the other passwords can be created the case of characters that form your original password.
For example, If your password is [email protected]!, you can convert the uppercase characters to lowercase (and vice-versa) and the change password string– [email protected]! – will also login into your Facebook account.
There’s another variation as well. If the first character of your Facebook password is in small case, just change that character to upper case – like [email protected]! – and Facebook will gladly let you in.
You may try these variations with your own password on the Facebook login screen available at facebook.com/login.php.
Thus, if you have accidentally enabled CAPS Lock on the keyboard, the toggled password would still work on Facebook.
Source: Digital Inspiration