In Mac OS you can make your computer look more like “you” with customizing the login screens.
Log-in screens are often just plain and blah. It looks the same on each and every computer. There’s that typical background, your log-in name and maybe a prompt for a password if you deigned to have one. You have to get past that log-in screen before you can customize your desktop to your own preferences.
Have your ever wished that there was a way to add more information on your log-in screen? Just to show your personality, perhaps? Companies assigning work laptops probably want to add the company name and an assigned to message so that it can be clear whose computer it is. They often customize login screens. People working on secure data may want to include a warning message. And in case of loss, you may want to include contact information so that your Mac can be returned to you (In a perfect world that is).
Well, with OS X Lion, you can now do that nifty trick of placing a custom message in your log-in or lock screen. All you have to do is launch your System Preferences, and head on over to the Security and Privacy preference pane. Tick the box to enable Show a message when the screen is locked and type in your customized message.