How quick would you expect wikipedia to be updated?

With respect to the latest terrorist threat, I wanted to know what PETN was and how complicated it was a substance to produce in an effort to decide which sorts of individuals might be capable of manufacturing it, so of course I wiki’d ‘PETN’ and found that the page had already been updated.

So my thoughts now are, can anybody tell me who updates wiki and how quick would you usually expect it to be updated?

Oh, an do you think its, well, just a little strange?