Hmm, I'm not sure what they are called. Last night, I left an email up on my screen. I had the program Caffeine on so my machine wouldn't go to sleep or go to screen saver. I forgot about this and went to bed. Seven hours later I am up, and when I minimized the email, the imprint is still on my screen (like a watermark in my background wallpaper)... I can read the whole thing. Now I know it isn't good not to let the screen saver come on, but isn't that a bit extreme? Seven hours? >.>