ICQ did too, IIRC, before it was integrated into AIM.

That was a setting and not on by default iirc. I had a 6-digit UID (edit: UIN, dammit), and I clearly remember activating it because I found it cool.

Edit: googling it I found someone else that remembered it: https://www.reddit.com/r/tipofmytongue/comments/2w4evp/comme...

Edit2: https://liferay.dev/blogs/-/blogs/10-reasons-to-switch-forwa... number 4

It also didn't work for people who were behind NAT, I think, and leaked the remote parties IP... so there may have been many people who used ICQ at that time but never saw that functionality.

I like it, and to this day there are some friends that I talk to using talk by sshing into a common host, just because the realtime typing is nicer.

wow, I had forgotten all about UIDs completely, and as soon as you said that, my 6-digit UID came right back to me like yesterday (260388). bizarre!

Was heavy ICQ user with low UID, rather sure it didn't.

Icq's chat feature definitely did around 97/98/99. I remember it being different from the IM feature in that way.

I used ICQ in it's original form and i don't think it did