All from at least 2.5/3.0 on was [email protected] for email. They were also not good at security, as you could spoof emails coming from any domain if you used their smtp servers directly - but they had regular email addresses. I never used compuserve or prodigy, however ICQ used numerical user IDs.
AOL and Compuserve — let’s use numeric addresses so it’s kinda like phone numbers, right?!
Also, whatever MSN tried to be when it first escaped from the lab.
Didn’t Novell have some kind of email-substitute messaging product that they tried to jam into their proprietary TCPIP competitor, as well?