What is information literacy? Cite ACRL or AASL standards all you want, but for many teachers and librarians, the definition is secretly, "Teach kids not to use Wikipedia."
Some level of concern is certainly warranted. After all, when dinosaurs in a webcomic point out credibility issues with this particular source, it may be wise to consider broadening one's horizons. But Wikipedia is far from the only source that has ever provided inaccurate information. Actually, it has become far more transparent about how accurate its information is, noting when a section of an article needs additional footnotes or clarification, or when it may not be grammatical or objective. Wikipedia arguably forces people to question where information comes from and think critically about it in a way that traditional encyclopedias do not. So why has it become the shibboleth for declining information literacy skills?
A great deal of the backlash against Wikipedia has to do with assumptions about what information is the most useful, reliable, and important. The academic community in particular still privileges print, the individual, and "the expert." It values being able to trace an idea, expressed in written language in a stable form, back to its source: the individual who worked hard to become an expert in that field. Plagiarism is the greatest sin, a form of identity theft--blurring one's own thoughts and ideas with those of another individual or assuming the individual's intellectual identity outright. The stability of print allows the individual to claim the right to his or her ideas and oust the pretender. Naturally, an environment with these ideals and norms would look with suspicion on a Web-based encyclopedia that is constantly changing and lets anybody--anybody!--contribute to it in a collective fashion. Why, you have no idea who said what, or when, or if they had the proper qualifications... It can't be authoritative if there's no source of authority!
Ironically, this distrust may be the perfect seed for growing critical thinking skills. But for students, the distrust may expand outward to more hallowed institutions. What makes a person who writes a book more of an expert than a person who writes a blog? True, the former may benefit from editorial oversight, but the latter has to face the immediate, public responses to a post, many of which can be critical and force the writer to elaborate on or correct the original post. It is misguided to say that one form is inherently more "authoritative" than the other. But it is perfectly acceptable to ask students to consider where the information comes from, how it was created, who created it, the benefits and limitations of its particular form, and whether it all adds up to something appropriate to use to solve an information need in the current context. Should you cite a Wikipedia article on The Sound and the Fury in a literary research paper? Of course not. Is it a good place to start if you're going on a date with a Faulkner buff in half an hour and you don't want to sound stupid? Well, why not? And who's to say which information need was more important in the long run?