Just a few seconds ago I finally cleared the checkbox in Adium for my ICQ account. It was my longest-lasting instant message service account, having been active since 1998 or so, and I started using multi-service IM clients like Miranda, Trillian, and Adium entirely because I wanted to keep using ICQ even though most of my friends were on AIM instead.
Times have changed of course, as far as I'm aware I have one contact on ICQ and I haven't used it to talk to him since AIM started to support offline messages. Looking at my Adium chat logs, since December of 2006 I have not sent a single message on ICQ and the only messages I've received are spam. With that in mind, it's time for it to go.