Every now and then a weird eyeball-looking icon pops up for a split second next to the 3G icon. It never stays up long enough for me to get a good look at it. What the heck is that thing?
That eyeball means you have "smart stay" activated. Every so often the sensor will look to see if you (or whoever) is looking at the screen. So long as it detects eye movement the screen will stay on. If it doesn't it will go into sleep mode.
It also doesn't seem to work very well. I can be looking right at my screen (in my well lit office) and see the icon pop up, the screen will still go into sleep mode.