It's the beginning of a new school year, so once again the fifth graders are being introduced to historiography—which is to say, being taught about "sources". Sadly, time does not permit the budding young scholars to investigate any topic more deeply than would be satisfied by a glance into their textbook, but form demands that they be taught at least two facts: that there are things called "primary sources", and that Wikipedia is not reliable. Naturally, the justification for this latter point is that "anyone can edit it".
You know that I think that's ridiculous. There are basically two reasons for there to be "false information" (quote-marked judiciously) on Wikipedia: vandalism and bias. Obviously, the first can't possibly be a problem in a traditionally-edited text, and so it is presumably the cause of teachers' concern. But really, how often is Wikipedia vandalized in a way that would trick even a fifth-grader into thinking that the vandalism was true encyclopedic content? If "ROSA PARKS WAS SO GAAY LOL!" makes it into a school project there are bigger problems than the student's choice of sources. Yes, we can imagine that there are people maliciously changing, say, the birth dates of obscure historical figures; but knowing that Ethan Allen was born in January instead of June is hardly vital to an understanding of the course of the American Revolution.
Plus, you may not be aware of this if you haven't actually read Wikipedia but there are some serious experts—and seriously dedicated people—posting things on that site. Anyone can edit, sure, but User:Magicpiano is going to edit a lot more often than any vandal, and he won't let any shit slip by that doesn't belong on that Ethan Allen page! Which is to say, obvious vandalism is generally dealt with instantly, and subtle vandalism will only be able to hang around on pages that no one is watching; pages that won't, most likely, be needed by fifth-grade researchers.
But what about bias? Surely the random... No, I can't even formulate a hypothetical that would make Wikipedia seem dangerously biased compared to any other historical source. Yes, I noticed recently that anarchists seem to be more active on Wikipedia than Marxists: witness the one-sided treatment dealt out to Hague Congress (1872). But the same research project also led me to A Concise History of the Russian Revolution, by Richard Pipes... who as it turns out was a Cold-War-era analyst for the CIA who argued that there could be no hope of detente with the totalitarian Soviet state. That doesn't make his book useless by any means, it just means that it won't be the only one I read on the subject. And how did I check on Richard Pipes, when I saw how many books he had written about Soviet Communism? I looked him up on Wikipedia, of course!
It isn't even as if that sort of bias is something that bothers fifth-graders—or their teachers, in fact—in the slightest. For the most part they limit themselves to the barest account of facts, and parrot those facts from whatever source they happen to find. Speaking as a historian, most things written for a fifth-grade reading level are, if nothing else, infected by the biases that are almost inevitable in that sort of simplifying and compressing. But that's a problem that is much too big to consider at the end of this already-long post, and one that has nothing to do with Wikipedia in particular.
One final point, just to drive home how much it bothers me to hear people complaining about the collaborative aspect of Wikipedia: Wikipedia is almost certainly the most reliable source about historical events on the internet. Yes, it's written an edited my many people, and you may not know who they are. But everything else on the internet is written by one person (well, one per page... you know what I mean!) and that person's motivations and biases, to say nothing of their actual level of knowledge, are just as opaque as those of the Wikipedia editors. School teachers can't say that kids shouldn't look things up on the internet—the internet is like all the rage these days, with the technology and the interfacing and everything—so they should lay off the Wiki-hate. And also consider getting a degree in history, but I understand if not everyone has the time for that.