How to make a unity application controllable?

Hey,

Suppose you have a unity application that displays information about the building you're in, like a dashboard of some kind. You want other computers on the network (local or otherwise) to be able to control what's displayed on this dashboard. Like send a command to this unity application to hide energy consumption, or show a new panel with X information on it, or change the color of something on the display.

How would you go about doing this (essentially, writing an API for your unity application)?