IRC has been in decline for years though many will not have noticed it happening for as long. Those, including me, that prefer to haunt small community-based networks will have noticed it more. It's much easier to see a decline amongst a few thousand or few hundred users than one hundred thousand.
IRC's first enemy was the instant messenger and there were at least four popular ones that poached chat traffic from IRC and IRC was often used as a spam method for those wanting to populate their lists of contacts. Then along came the first social networking websites, joints like MSN Spaces and MySpace. After that came Facebook and Twitter. In a few years Facebook will die off because of their apparent flagrant abuse of user privacy and their datamining activities. Something else will come along and take over that.
Will IRC continue for the foreseeable future? I think so. There's no reason why it shouldn't although IRCd server development is not exactly continuing at a frantic rate either. Once we could expect huge server upgrades every three to six months. Now we'd be lucky to see a bugfix release once per annum unless one goes for an expensive package like ConferenceRoom. For the more traditional server software packages, it is looking like the end of the road for further advancement - there's only so much one can add to a system that is more or less just a text-based chat protocol and let's face it, with most IRC users that is all they want - raw text.
Kids as young as ten are being weened onto social network sites and they stay there with the same type of addiction that IRC users once had. There's little chance of them considering a move to IRC.
Finding an active IRC server could be as close as typing "Chatroom" or "IRC server" in your favourite search engine.
