If everyone one in the world were positive thinking and nice, it would suffice to grab a perl telnet server (or web server) and simply eval every command sent to it. In no time, people will have built a complete MOO.

In practise, you'll have your server reformatted in no time flat.

So you go back, and try to sanitise people's commands, or switch them to a language like lisp or BASIC. You provide a backend object database, perhaps implemented with hashes (each key is an attribute for an object), overlay a security system for authenticated users (so they can't edit each other's hashes without permission).

It's one of the best examples of Model-View-Controller programming in the world.

I have a friend currently running up a MOO on our server. If you would like, I'll introduce the two of you. I'm sure he'd be interested in talking MOOcode for a bit.