It was also a great place to vent anonymously when I was at the lowest points of my life, in a judgement free environment. I don’t think any social network will come close to capturing the effect of IRC. Decentralization and federation are what makes it a great protocol, IMO.
BBSs were more of the than not local, with some federation in that the operator or someone he trusted would exchange data between the local BBS and some distant BBS.
Similarly IRC used to house a high number of very local channels back when i first came online (and one tried to pick a server on the network that was in one's own nation or a neighboring one to avoid finding oneself on the wrong end of a net split).
Social networks offers much the same via various means (groups on facebook, sub-reddits on reddit, etc).
Honestly IMO, what killed IRC was IM and SMS. This because now the schoolyard cliques could once more ostracize.
IM definitely took the bite out of IRC because it was far better at creating beginners that never made it to IRC, and a lot of IRC users got pulled to IM. ICQ, Yahoo, AIM, MSN created a new type of connection.