I’m 2 degrees of contact away from the inventors of ICQ. We have a family friend who is a diamond salesman from Isreal. Before he moved he was friends with the folks who would go on to found Mirabilis.
Fun fact, literally the entire reason ICQ was developed in the first place was to facilitate voice chat while playing multiplayer flight-sim type games. They were all sons of well off diamond merchants, and all had killer setups. Force feedback, surround sound, those fucken chairs that move around and shit, the works.
They got startup money from one of the dads and blew up just from word of mouth. 2 years later they sold to AOL for $407 million, and 12 years after that AOL would dump it for less than half of what they paid.
My dad registered his account around 1997 and had a 5 digit ID. By the time AOL bought them they had somewhere north of 2 million registered users.