Thanks folks, those look like some really promising options. I'll be especially interested in anything that takes the graphics/memory/processing load off of the client-side browser. But at the same time, I assume that the server will be running a single instance of the "game" (virtual tour in my case) that any number of people will be able to connect to through their browser and experience their own session independent from what other people are seeing in theirs; sure, in a multiplayer game you'd want them to interact with each other, but in my program I don't want them to, I just want them interacting with the program...

And, if Conitec ever decides to develop/acquire their own option for this kind of native functionality, that would be super awesome!