I can fairly say that it was IRC that introduced me to the coding world (where I learned to code TCL scripts for Eggdrops) when I was in high school and made me decide to switch my major to Computer Science after my first semester as a Graphic Design student (which I only chose because my brother had switched off Internet access from me for a few months which affected my judgment apparently)
I'm of a generation after you, likely, but I'm in the same boat. I learned python by maintaining an IRC bot, which started out rolling d20s. It then expanded into a 1000+ line monstrosity, which was a mess, but the features taught me many aspects of programming, and let me apply it. The bot has since been rewritten into much, much cleaner code, and is one of a few projects I'm proud of. All thanks to RFC1459.
One of my greatest achievements back then was allprotection.tcl[1] (over 2000+ lines of spaghetti) LOL but I have no doubt that TCL scripting taught me a lot and gave me a huge advantage during my studies!
Hah, looks better than my original code. When it was starting to be created, I didn't even know how to write a function, and there were a grand total of I think two when it was retired. Here [1] is my updated code. Apologies for some edgy commands, my IRC server has some... interesting people in it.
IRC is what introduced me to client-server architecture. Like many back then and still today I had this vague idea of "server" meaning some kind of powerful computer with no monitor. I used to love IRC but I was only in dialup Internet and wasn't allowed to use it very often. I sorely wanted to be able to idle on IRC at all times like some people did. But then I discovered I could actually install unrealircd on my own computer! I had my own little network with eggies talking to each other. I experimented with different clients and even connecting manually with telnet. It was great!
LOL I used to go to network cafes to be able to connect before we finally had cable internet at our place (dialup was too expensive). Since you mentioned "idle on IRC at all times", me and a friend of mine (who I still work with to this day!) used to sell shell boxes for people to install PsyBNC and Eggdrops on. First brush with business, those were the days haha