IRC is the epitome of the internet. Only downhill from those times. :/
The core idea is there's an optimal number of people. Not enough people and the community dies: not enough activity and ideas to sustain it. Too many and it also dies: it becomes impossible to form social relationships, cooperation dies down, everything becomes meaningless because you don't know anyone, the probability of ever interacting with any given person ever again trends toward zero.
Made a lot of sense to me.
(admittedly I haven't tried anything other than a few basic IRC chats, never really getting deep into IRCv3 or new features and stuff)
Email is still a great way to communicate with people today.