The splash site states that this mouse was over 2 years in the making. Hundreds of prototypes were created. Ultimately, the researchers settled on a capacitative-sensing model, which almost works like a touchscreen. The time was spent building a gesture recognition engine and refining the sensor design. The Touch Mouse features seven finger gestures, which will allow you to do the most common tasks in Windows 7, like opening files, moving between windows, and switching tasks. The mouse will also allow you to use your thumb in the gestures and will only work with Windows 7 when it's released in May for $80. The mouse also uses BlueTrack technology, which functions on almost any surface.
We're also curious to see if Microsoft will release something like the Apple Trackpad, as many users have migrated from the Magic Mouse to the Trackpad because of the overall size of capacitative area on the Magic Mouse. Apple has had a lot of experience creating touch-based UIs thanks to the iPhone, iPod, and iPad. This has translated in stellar performance in OS X, especially on MacBooks with their trackpads.