ICO, as in Ironclad Online, if you played online multiplayer
I could swear that said "ICQ" before.
...Then again, I was reading on a phone screen.
I never actually played a match online, but I did create an account. E-mail, away!
[EDIT]
Got an auto-reply saying to contact [email protected] for lost serial keys, among other things. So, for future reference, that's where to go for this.