You know that little audience reaction graphic that CNN puts on the bottom of the screen during debates? I want one.

OK, backing up: as I understand it, CNN puts about 80 people in a room in Ohio to watch the debate and equips them with little dials which they can turn left and right to indicate, on a scale of 0 to 100 . . . something. I'm guessing the dial setting is supposed to correspond to how much people agree with or identify with what's currently being said, but it really didn't say; unfortunately CNN didn't give any vertical scale other than "+.....-" (Note to anyone who wants to do better-than-useless data analysis: this is a Very Bad Idea. Always label your axes.) Anyway, the graph at the bottom of the TV screen shows some sort of average opinion over the focus group, split up by party affiliation or gender or whatever.

During the second presidential debate last night, I started thinking, why couldn't we the people pull this nifty trick for ourselves? It should be pretty easy to emulate CNN's dial gadget with a small Java applet to allow people to contribute their opinions over the internet. Of course, the UI part would be pretty trivial. The problem, I think, comes in when we start to consider communication.

The most obvious way to implement this is a simple client-server model, in which each contributing applet (client) reports every change in its setting to the server, probably with a UDP packet. In that case the data rate received by the server would be O(n) in the number of clients. The client would also have to display a live feed of the average opinion, which means an outgoing data rate from the server of O(n) if we send out updates at fixed intervals. The thing is, for anything more than just a few clients, this can put a lot of stress on a server like, say, the one this website is hosted on (which is the only one I have with a static IP address).

Of course, the simple client-server model probably isn't the best way to set up the system. It could use a hierarchial network structure, with the main server at the root, which could decrease server load to O(n^1/k) for k = 2, 3, 7, whatever...but that could get pretty complicated. The point is, I'd love to be able to get something like this ready for the final presidential debate next Wednesday, but I don't see it happening in a week. Maybe someone else is doing this already - actually, I'm kind of surprised I didn't find it out there already. Oh well, here's looking to 2012...