Even before SideShow many PC geeks (especially on Linux) have been using USB LCD displays, which are small monochrome displays that plug into a USB port and can provide system diagnostic information (temperatures, fans speeds, etc.) or even, with the proper drivers, indicate new email, etc. Unfortunately, OS X lacks any kind of drivers for these secondary displays, though someone has managed to build LCDproc for OS X. Personally, I'd love to have something like SideShow for the Mac, either built-in to the outside of a new MacBook, or even on something like Emtrace's stand-alone WidgetStation, which would run Dashboard widgets. With the iPhone apparently having some sort of widgets, Apple is already moving them beyond the desktop, so it wouldn't even be that much of a stretch.
So what do you think, TUAW readers, am I nuts for thinking Microsoft has a cool idea here?