IRC - ​Internet Relay Chat is a text-based group communication tool. It is a useful way for a group of people to gather around and discuss a topic, and popular with groups of open source developers.
If you are new to IRC, the first thing you will need is an ​IRC client. A popular client for macOS users is ​Colloquy.
Once you have your clients, configure it to connect to an IRC server, then join the channels on that server that you are interested in.
We are presently using the following IRC channels. All of our channels are on the ​Freenode network.