the iPad follows our posture - it is so intuitive. Great comments! Thanks All of this information is well and good Ernie, but I've looked over all your blog entries visible without going to archives and it seems every one is either 100% about the computer. I understand Think of the backlight as a thin fluorescent tubelight that powers up the monitor screen. Most backlight bulbs have a lifespan of 3, 5 or 7 years but you might notice the screen go dim & dark as early as 2-3 years.