You want to see one of the most fascinating uses of IRC in a focused, dedicated community let me introduce you to the player group known as the "Fuel Rats" of Elite:Dangerous[1]. They use IRC for far more than just a hub to congregate and socialize, 100% of their actual dispatch operations are planned, coordinated and excuted on IRC.
If you run out of "fuel" in game, and you need a Fuel Rat to come rescue you, you do it in IRC. Dispatch talks to you in their IRC channel, other dispatchers are communicating in NOTAM[2] like notation with pilots out 'rescuing' other players.
You did say up to 2013. I know a lot of games that were heavily IRC based in coordination, but move on to either Slack or Discord around 2015. Though the link suggests it's still IRC main.
No, these are actual In-Real-Life-People. Maybe parent got their dates a wee bit wrong.
When I started playing Elite:Dangerous (circa release date 2014?) I ran out of fuel in a system I couldn't refuel in (wrong type of sun or something like that)...and so was stuck. The only way out was to self destruct.
After some googling I discovered the Fuel Rats on Reddit and then their IRC channel. So as per their S.O.P. I put out a call for assistance on their IRC channel and within 10-15 mins or so one of their crew appeared in-system and refuelled me. I don't like to abuse the word "awesome", but these folks were awesome. They were like the AA or RAC of the galaxy :)
The service is entirely free, in game and out of game. Fuel Rat 'rescuers' (or just 'fuel rats,' there might be a better term they use) do it for the fun of it. It's an amazing example of emergent gameplay.
I've been saved once or twice by fuel rats. The process is fantastic and seeing the dispatchers in action is fascinating. After they refuel you, they give you a little talk and help you avoid running out of fuel again.
"Right when Elite:Dangerous was coming out, I had just quit a 3-year stint of playing World of Warcraft ... When Frontier decided to add a feature to the July 2015 release, consisting of a refuelling limpet/probe that could be used to transfer fuel to someone who was out, I had a brain-flash and did a posting announcing that I was starting an organization called “The Fuel Rats” who would undertake to rescue people in-game who ran out of fuel. And, The Fuel Rats were an unexpected success ..."
Put me into the "they should move to Discord" crowd.
The hardest part of using their (really good) services was having to use IRC. If they'd used Discord, I'd hop into a server effortlessly. Instead, I had to navigate the byzantine vagaries of terrible UX while running out of oxygen. D:
This is 100% just how you feel, and it's not based on facts. IRC clients come in many varieties and the basic functionality matches Discord in ease of use.
Depends little bit, what you want. I don't like irssi too much, but for something over gnu screen or tmux this is pretty usable for longer sessions, collecting channel conversations (so, poor man bouncer + client setup).
HexChat is decent Linux or Windows client. When I used Windows, I liked mIRC, this was (and probably is) very versatile. I have seen customisations where you don't even feel that mIRC is used.
I think another good example of IRC usage was the channel for kimchi and its associated tools. It's a GUI for libvirtd but the interesting part is that they used to hold daily standups in IRC.
Just like we do today in Webex Teams for example.
I personally never liked the transition to web based chat because IRC was a lot more information dense than any web chat can be.
Being able to paste inline code doesn't sell it for me since there are pastebins you can host on prem easily.
If you run out of "fuel" in game, and you need a Fuel Rat to come rescue you, you do it in IRC. Dispatch talks to you in their IRC channel, other dispatchers are communicating in NOTAM[2] like notation with pilots out 'rescuing' other players.
It's amazing to behold.
[1] https://confluence.fuelrats.com/display/FRKB/Rescue+Standard...
[2] https://en.wikipedia.org/wiki/NOTAM
Disclosure: Fuel Rat 2010-2013, Retired.