I'm a moderator on the site and I've worked a bit on the client and know the admins/developers. Currently the client you see on that github (https://github.com/OurSources/owop-client) is mostly up to date, but the current server is private. The server is written in C++ and uses synchronous disk operations, which makes it quite slow when lots of people are online like right now. A rewritten and improved version of the site should come out by the end of the year.

The server runs in a single thread, so it's not really possible for two websocket messages to come in at the same time. One edit will come before the other, and the later edit is the one that everyone will see.