This made me realize that I still remember my ICQ UIN! I cannot remember what I've had for lunch yesterday, btw.
I forgot my ATM PIN though.
Mine also began with a 2. It was 279866. My girlfriend’s was slightly lower, as she introduced me to the new service. We both felt like pioneers in those halcyon days.
Mine was quickly usurped by a Russian hacker. The profile was replaced by Cyrillic writing. I never knew how they did it. None of my other accounts or socials have ever been usurped like that!
It's good to finally know there was a critical flaw like the one in OP that was likely used.
And also yes, the last time I looked, my account was all cyrillic.