Ughhh I hate having to sound like a responsible adult, but like, I think this email argument is getting a bit circular and you guys are never going to agree (I don't care enough to include myself in the "you guys").
Also, if MUDs are included in MUs, sometimes they're a business. But that's just nitpicky on my part.
While not a problem, more of a "this would be cool", I wonder what would change about the culture if more MUs embraced IC channels (IE: channels that represent internet, radio, phone, etc). Some private, some public, representing different areas of communication. I've always enjoyed games with them. Well, some of the games I play have moved beyond simply channels and already have their own uniquely coded systems for IC communication outside of a scene itself. I find them to be very convenient and fun, when properly moderated.
I say when properly moderated for reasons that anyone who played MCM 5 years ago or M3 2 years ago should know. Everyone else should just take it as an ominous warning that you don't want unregulated public IC channels. Private ones don't need to be regulated, really.
If I recall correctly, I think Reach had a channel for IC radio shows, that was fun. But that kind of concept can be taken much further (and has been many times).
When I make my game, I think I'm gonna give scouters access to a chat system that is limited to 140 characters, because fucking hilarious.
edit:
"Omg all these dickpics!"