I dont think IRC is dying, for some purposes having real time chat is better then posting on a forum and waiting for somebody to read and reply.
Newsgroups have less people these days becasue of SPAM, if you reply to a note with a real email address you get spammed to death. The good thing about newsgroups is that you can reach one hell of alot more people since there is generally 1 amiga newsgroup compared to dozens of amiga forums. Also it is very easy to google an old thread from a newsgroup to help you fix a probem.
I used to use ICQ alot for keeping in touch with people but forums, emails, and the ocasional irc chat are about it these days.