Here is what, for many, is a weak point in wikipedia: the sources. What is accepted as “true”. Here is a list of claims that may have been challenged in wikipedia, or not. See how many you get right!
- About the katakana Japanese syllabary: in a manga, the speech of a foreign character or a robot may be represented by, for example, コンニチワ konnichiwa (“hello”) instead of the more usual hiragana こんにちは.
- About Hugo_Stiglitz (a character in Inglourious_Basterds): Fittingly, the character’s guitar riff theme is taken from Slaughter, a blaxploitation movie starring Jim Brown.
- In the article about the film Watchmen: Classical music excerpts include Wagner’s “Ride of the Valkyries” in a Vietnam battle (a reference to Apocalypse now) and Mozart’s Requiem at the resolution in Antarctica.
- Getting serious: In the article about the well-known D’Alembert’s_paradox of hydrodynamics: Recently the following alternative resolution of d’Alembert’s paradox was claimed  … This is a different resolution from that by Prandtl and it is claimed to be supported by both theory, computation and experiment. Notice that Refs. 7, 8, and 9 correspond to two articles in peer-reviewed journals and a book published by Springer!
- Of course, millions of people know Japanese and read manga, so a source is not provided.
- Of course, dozens of people know about mexploitation, blaxploitation and Jim Brown. So, this claim can be read in the current article, with no reference whatsoever (!).
- Of course, millions of people know this music, it being Wagner’s and Mozart’s (and not too obscure pieces!). But see, technically that was just my opinion (that’s right, that was my little grain of sand, see the old entry). I did not provide a reliable source, so it was deleted. See the comment on my talk page.
- This is serious stuff: see a summary of the controversy. Despite the strong support for this claim, it seems all reference to this line of work is being systematically deleted! Among the abundant discussion, one reads things like: I find your claim as to the prestige of the journal surprising. It was started in 1999. Is a publication in that journal the pinnacle of the subject of fluid mechanics? I don’t think so. Perhaps to give me an idea…what is its impact factor? OK, so we are now talking impact factor in order a article published in a peer-reviewed journal be taken as a serious source? What’s next, something along “yeah, but that’s a Phys. Rev. E, not a Phys. Rev. Lett.“?
To summarize: I think the lack of a clear definition of when to use a reliable source, and what constitutes one, is a serious problem in the wikipedia project. Not an easy one, I am aware, but I think not even including references to controversial approaches, like in the last example, is definitely going too far.