The popular thing to do these days is to offer a “slate” style smartphone where the front is virtually all touchscreen and that’s about it. However, sometimes you want more functionality and it looks like Microsoft could be moving in that direction. Based on this patent, it looks like the Big M is working on a slider phone where the lower portion is modular in scope.
Basically, you get an empty slot in the slide-out portion where you can insert various modular parts. Want a slide out QWERTY keyboard? Put in that component. Feel like playing some games? Insert the gaming controls. The same spot could be used for extra batteries, a secondary display, or any number of other possibilities.
The modular components may have a physical connection to the phone somehow or they might communicate wirelessly via Bluetooth. In any case, this could offer a huge level of versatility, though it could come at the price of increased complexity, cost, and chunkiness. That and the last time that Microsoft tried to do cell phone hardware, it didn’t go so well.
It’s interesting, to be sure, but it’s yet to be seen whether this would be practical in real life conditions.