I'm not sure if this is the same exploit, but there was an exploit where you could steal usernames from people during signup. The victim's username had to be an AIM-only account (never linked to a paid AOL account). Then with some sorcery, you bypassed the "invalid name (already taken)" UI block and the backend would make an AOL account with the username.
I stole "christ" from someone this way. Sorry, Chris T. I was 16 years old. A friend stole it from me later, and then someone TOS'd it after that (banned it using a mod account).
Random people would message the account all the time, as if it were actually God, and ask for advice. 16 year old me did my best to give well-considered advice.
> including one where he stole pretty much every 3char name available
Interesting. I think people in my friend circle were in possession of two until AIM pretty much died ('zad' and 'baz'--only 75% sure I got the 2nd one right). Guess they got lucky!