Discord

Discord is a chat program usable as an alternative to IRC.

Like IRC, it is structured around channels on servers, but unlike IRC a given community (like geohashing) will generally operate their own server, with channels per-topic (well, Discord the company hosts the storage and bandwidth and does the technical operation, but rarely becomes involved with moderation). Another difference is that IRC accepts any username whether or not it has been previously registered, and only after joining a server is registration of one or more nicknames possible (through NickServ). Discord, however, requires registration up front, although pseudonyms (both globally and per-server) are fine.

There is currently a geohashing Discord server thanks to user:January First-of-May.