The pink dot is similar to a web bug and is used to formulate the amount of clicks to a particular start menu.
But in all seriousness, It is actually a thermal sensor that is used to turn your monitor into an imaging device,
They can now make a picture of yourself right through your monitor. This is Big Brother at its best or worst. Imagine what they have already seen.....
Microsoft has developed this technology that dot dithers your screen to act as a camera receptacle. As you will see, the beta web site captures your image just as if you had the computer connected to a video cam. This technology may have been around before XP and installed on web sites without our knowledge or permission. If so, those web sites are capturing images of you unaware as you view your monitor.