TweetIt's just a thing that keeps the image on your screen from ruining your monitor. If you constantly leave images on the monitor they will burn the image into it and then you will have a crappy image. I personally set my monitor to do that after a few minutes of no activity just to make it last longer. I have an LCD one now so it may not even be the same as the older ones but I have ruined regular monitors by leaving images on them too long.