It'll all be digital. Imagine a switch consisting of a spring, a coil and a magnet. The coil could pick up the magnet's location, as well as move it in response. Essentially, each key would be a tiny servo.
This would let people use a single keyboard for everything. You could "install" a new keyswitch for gaming, typing, browsing the web. You could have keys return harder than they were pressed, or move slightly in response to things happening on the computer. Different keys could move differently, or could even adjust their properties depending on which other keys are pressed.