FWIW, I've also realized that my Yahoo account from circa 1996 works just as well. my.yahoo.com even remembers what news topics, stocks, weather locations, etc I setup nearly 20 years ago.
I miss ICQ. Well, I still use it occasionally, since it's part of my MirandaIM setup. But I miss it whenever I use Skype for IMs. For starters, I can aggregate ICQ, Jabber and a bunch of other services inside one lightweight open-source client. Also, it had an entirely different social vibe, which is missing from Skype. It was okay to chat with near-strangers in ICQ. It was okay to add people from some random forum to your contact list. It was okay to say "hi" to people when they went online (as opposed to always-online on 10 different devices Skype mentality).
When I first used ICQ in 1996 (a buddy introduced it to me) I couldn't figure out who'd be in front of their computer that often. Plus the 90s was still largely on dial-up as well.
EDIT: I guess I was wrong... https://www.icq.com/support/icq_7/messages/is_my_message_his...