It's similar, I suppose. Like the Wikimedia example, the Lua you write for WoW is tightly limited -- there's an API available [1], and you can request some extra data from the server sometimes. However, there's absolutely no loading of external modules, contacting any sort of outside server, or any direct file access. There's also large swaths of "what the player can do" which are blocked off from the API, in the name of not allowing people to automate core game elements.

[1]: http://wowprogramming.com/docs/api