Try to look beyond that filthy smartphone JPEG compression to get glimpse into the future of auto mirrors.
The NeoView Kolon is a prototype that uses a transparent OLED display, presumably layered over a reflective mirror. The result is a HUD of sorts...that could probably be extremely useful if it didn't expend so much light and distraction on looking cool.
For instance, a bumper mounted camera outfitted with the proper algorithms could track the speed of incoming vehicles. This data could label incoming fast cars on the OLED, alerting the driver to allow some extra breathing room in his lane.