Many players of today's virtual worlds may not realise it, but there are actually two strategies for resetting "used" content. The more familiar one is respawning, whereby an object or mobile or puzzle is restored to some variation on its original state after a period of time. Sophisticated versions of this can involve spawning different things depending on the current world state (for example sheep instead of wolves).
The other strategy for resetting is the sudden reset, also known as the groundhog day approach. In this, it's not individual content items (or linked collections of them) that are respawned, but the entire virtual world. The advantage is that quests, puzzles and game-like content can be far more complex and intertwined, because they don't have to be unpicked a thread at a time. World-altering events can occur - cave systems flooding, mines collapsing, volcanoes erupting - which have so many causal effects that it would be impossible to follow every one through to undo it. The disadvantage, of course, is that everyone has to be dumped out of the virtual world while it resets, which inevitably occurs just at the precise moment you really rather wish it wouldn't.
How about a hybrid approach?
One of the "new ideas" of (graphical) virtual worlds is instancing. In this, a group of players get together, press the magic button, and a pocket universe appears just for them. Their characters can go in, explore it, plunder it, whatever, and then when they leave it simply disappears. In other words, it resets when it's played out - classic groundhog day territory. This leads to the possibility that such pocket universes could have much richer and more fulfilling content than the greater virtual world that hosts them. Indeed, if they become large enough they could be considered as bona fide virtual worlds themselves, with the host world a kind of theme park that gives a context to the individual rides that are its sub-worlds.
OK, so this is something which may interest virtual world designers, but it's not really Terra Nova material. Don't worry, it becomes so shortly.
Note that although worlds that reset through respawning can have sub-worlds, groundhog day worlds can't (or rather they can, but the sub-worlds will all reset when the host world resets, so they can never be truly independent). This means we have a hierarchy of worlds:
1) The real world.
2) A non-game, host world (such as SL).
3) A game-like world that resets through respawning (such as DAoC).
4) A game-like world that resets in groundhog day fashion (such as, ahem, MUD2).
Only 1) is mandatory: it's possible to have any of 2), 3) and 4) without the others. The hierarchy is strict, though: you can't have a 2) dangle off a 3), because that makes the 3) itself a 2). You can, though, have a 2) host a 2) or a 3) host a 3).
So we have a tree. We can envisage several non-game worlds, some of which host non-game sub-worlds or game-like worlds that reset via respawn. Not all game-like worlds will necessarily be embedded in a host virtual world, yet some of them will themselves have game-like sub-worlds or groundhog day worlds embedded within them. Not all groundhog day worlds will be necessarily associated with a respawning world: some may be embedded within a non-game world, and others may be stand-alone.
And now, finally, to the point of this post.
Suppose you're heading up a guild that's entered a pocket universe which has been "spawned" from a game-like virtual world. This game-like world has been coded by a bunch of people, open-source fashion, to run in a generic environment operated by a hosting company based in the USA. Code permitting, who gets to say what one of your guild members can and cannot do within that pocket universe?