MSN was my main teenage way of communicating, aside from texts ofc because back then we didn't have smartphones so we couldn't have MSN on the go d: only at computers.
Then came Skype as a better alternative when I was in my early 20s I guess, and we used it for a long time. Crazy how Discord has only been big (in my world) since 2016 or even later. But now with smartphones and stuff it's easy to use any app of choice, desktop or mobile doesn't even matter much anymore.
I've basically never used AIM/AOL or whatever that is. IRC? I remember PC had some form of chat place with it? But I never ever went there. I hung out in our staff or RP based Skype groups until we made the Discord server :)