I, JohnLennon himself, lord of all ICQ, recommend that you check this blog on the second of December and attempt to enter chat through any of the embedded links here. If they do not work, ICQ chat is completely dead. If they are still working, the service has merely disabled the web page of ICQ chat itself, probably because nobody uses it, and has left the service essentially the same.
There is no definitive way to tell, at the moment, which will be the case.
Don't mind my disheveled appearance; not long ago I got done with some "up before 6AM" work. At least I don't look like Baaaz.