Internet Relay Chat is one of the older internet protocols, it allows real time chat and is arranged in a series of rooms or channels. Each channel has a particular topic and when you are talking in that channel everyone else sees what you say. You can think of it as being like twitter except hashtags are more important than followers – and there are not so many cat pictures.
You can join in on IRC with a web browser or dedicated IRC client, there are several included in the Ubuntu repositories. Xchat is quite nice. Our main channel is #ubuntu on irc.freenode.net where we are very focused on answering support questions. For anything other than support questions or answers we have an assortment of other channels. In almost every country we have a LoCo team channel, you can join #ubuntu-<iso code of your country> to jump into that channel and start talking with people near you. A fairly comprehensive list of our channels is available. We have some general guidelines on how to use our channels and a specific guide for people offering to assist others with support problems.