Do people still use IRC?
PrevNode LinkNextYes, they/we do. Old ≠ bad.
Some advantages of IRC are:
The protocol is simple enough to allow implementing mostly reliable and secure IRC servers.
The protocol has open specifications, and some FOSS servers and clients.
IRC chatrooms, which are known as "channels", are more discoverable than those of many newer services which have paranoid "privacy" measurements in place. E.g.: Python's channel is usually called "#python" or "##python".
See my mini-essay about paranoia.
Moreover, a new channel can be allocated fairly easily.
There are several separated IRC networks, so if one exhibits an issue, others are often unaffected by it.
The IRC protocol is fairly lightweight, fast, and responsive.