I hacked this whole thing together in a cafe in Paris over a couple days. It's not exactly what you'd call "scalable" ;). Given that it keeps a long-running streaming http connection to every client, it'd be expensive to set up servers to support this.
Is Paris dangerous now ?
Beats me? I was on vacation there 4 years ago. :)
I'm sure a $5 digital ocean droplet would go a very, very long way.
How could someone make a prototype for "monstrous chat" and not include a demo link with a monstrous amount of users.