"Exactly what in the world is this thing?"
Originally starting life as a replacement MSN Messenger server, Escargot is now an open-source chat server aiming to support as many chat protocols and systems as possible and implement them as frontends. As frontends, these chat protocols and systems will then be able to globally integrate accounts in our system and allow messages to be sent and received from other frontends. A list of supported and planned frontends are available here.
While a work-in-progress and experimental, Escargot is perfectly usable in most cases and is even preferred to from mainstream messaging services by some of our users. Creating an account is easy and only takes a couple minutes, and then you have access to our federated chat-o-sphere! The server, this site, and the components used to patch clients to connect to our services are also available under their own GitLab repositories. Like we said before, Escargot is open source. ;)