I'd bet there are plenty of people in SL and at LL itself who have used a MOO in the past...
For those who haven't, MOO stands for "MUD, Object Oriented". It's a text-based virtual world server, essentially. (See the MOO home page for more info.)
Lambdamoo's object-oriented style of programming seems like it'd be *ideal* for SL.
I still actively participate in one MOO on a daily basis -- and dabble with its nameless scripting language quite frequently.
Pros:
It's open source, it's been around for quite a long time with some brilliant people to work out the bugs.
It's built around discrete objects from the ground up.
It's fairly simple, but very powerful -- it does many things that LSL can't, and it does them *very quickly*.
Nested Lists. (Also, access lists via simple array notation... i.e., list[4] is the 4th member of the list.)
User-definable object properties and methods (called "verbs" in MOO-speak)
Cons:
It's not multithreaded, so lacks sync options that SL would need.
Anyone else have experience with this who'd like to chime in on why this is a good or bad idea for Second Life?