I'm not a web developer, so I wouldn't be the best person to ask, but the key aspect is that the server pushes data to the browser as soon as it gets it rather than waiting for it to be requested, right? You could call it "low-latency push" or "low-latency remote interaction" or something like that.

Or you could cut to the chase and call it "websockets." socket.io supports other technologies for ancient browsers, but that's a detail that could be addressed in the post.