This question is fairly simple, though I'm not sure the technology exists yet. I'm building a responsive version of a website to be optimized for use with a tablet device. This is one challenge itself, but another one I've been pondering is this:
When a user activates a keyboard, lets say on focus of a text input, can we A) recognize this and B) respond to this? In some tablets, the keys take up a significant amount of real estate and in some cases that can be less than helpful. If a user is, for instance, typing into a dynamic filter (i.e. Google Instant) that is immediately responding to their results, they have use for both the keyboard and the screen. This leads to a challenge for designers, do we create (or CAN we create) a design that responds to native mobile behavior such as keyboards?