11/09/2017 (Thu) 06:34:32
IRC is still alive and well, if you know where to look. Some websites still use it for their chat backend if they aren't using XMPP or some proprietary nonsense.
It went "underground" largely due to instant messengers which have the same functionality (and more) and Facebook (which has its own built in instant messaging). I think some of it also has to do with the fact IRC is insecure by default, and securing it is a pain in the ass to the average user (not to mention relies on everyone else doing the same). There are also botnets like Discord which are simply more convenient to use. IRC is still pretty widely used for piracy as an alternative to usenet (which still has not died out either). A few imageboards (Lainchan and 8chan I know of offhand) still use it as a secondary means of communication. A few obscure gaming communities use it as well.