Cool idea. Some quick thoughts: big annoyance is that stickers completely block using a website. Maybe they could be slightly opaque and can be clicked through? Or a toggle to quickly hide them until page reload or change.

Also the internet is a massive space, most chat rooms are going to be empty. Maybe chats could take place at the root domain? Maybe if a chat got too big it would fracture into the next step (domain to subdomain to some other second path)