Made my first contribution to the Wikipedia last night/today by correcting, enhancing and adding to a couple of the pages: one about Yosemite, the other about National Parks which references Yosemite.
Lots of stuff going around the blogosphere lately about the Wikipedia and how reliable it is (or isn’t, depending on your viewpoint). Probably in a year or two it’ll be at least as accurate as any recent treeware version for non-active entries, assuming publishers of said treeware don’t sue the Wiki out of existence because some people are copying verbatim from the text of their dead-tree version(s).
Personally, I’m not too worried about the Wiki’s authority because no one should rely on a single Internet-based source for accurate information; two or three sources, at least, should be considered good practice, just like with non-Internet-based resources. The people that do rely on Wikipedia for 100% authoritative info are probably the same people who rely on television or print media, both of which tend to get their info from the same one or two sources these days, for accurate information.