Real-Time Interaction Between Maps With Socket.io and JavaScript

I was doing some thinking recently. I was thinking about how I could make maps more useful than just displaying visual content on the screen when requested. While displaying map information on a screen is useful in many circumstances, it doesn't make for the most exciting of examples. This lead me to thinking about things from a more interactive level.

Take the example of first responders, such as law enforcement, fire, and medical. It might not make the most sense for them to be looking and refreshing a map to find incidents. Instead, what if the map automatically refreshed and was synchronized between the first responders? What I mean by this is, what if incidents automatically appeared on everyone's map at the same time without interaction?