Nevada Supreme Court on Reference Works with Reader-Generated (and Largely Unedited) Content:

The Nevada Department of Motor Vehicle refused William Junge's request for a personalized license plate that read HOE; the DMV reasoned that "HOE was slang for 'whore.'" (Junge said it was short for Tahoe, and part of his overall Tahoe theme for his car: "Although Junge would have preferred TAHOE for his plate message, he settled on HOE because his first choice was unavailable. For his plate background, Junge initially selected the Lake Tahoe panoramic setting to adorn his 1999 Chevy Tahoe.")

The Nevada Supreme Court, in DMV v. Junge, reversed the denial of the plate, but its reasoning goes beyond the surprisingly substantial but rather frivolous field of License Plate Law:

[B]y its own admission, DMV based its decision solely on the Urban Dictionary. Moreover, DMV revealed a policy of only consulting Urban Dictionary to determine if a word is inappropriate or offensive.

Urban Dictionary is predominantly an online dictionary, although a paper version based on the online content was published in 2005. See (last visited June 10, 2009). Its definitions are user contributed and are generally anonymous. There is no limit to the number of definitions that a user can contribute.

Since definitions are user contributed, they can be personal to the user and do not always reflect generally accepted definitions for words. See generally (last visited June 10, 2009). In fact, Urban Dictionary acknowledges that "[i]ts content is frequently presented in a coarse and direct manner that some may find offensive." See (last visited June 10, 2009). Moreover, Urban Dictionary readily admits that it "cannot control all [c]ontent posted by third parties to the [w]ebsite, and does not guarantee the accuracy, integrity or quality of such [c]ontent." Id. Furthermore, Urban Dictionary concedes that it "does not and cannot review all [c]ontent posted to or created by users accessing the [w]ebsite." Id. Thus, Urban Dictionary allows, if not encourages, users to invent new words or attribute new, not generally accepted meanings to existing words.

We acknowledge that the Iowa Supreme Court upheld the use of [Jonathon] Green's Contemporary Dictionary of Slang (1985) to review personalized license plates in McMahon v. Iowa Dept. of Transp., 522 N.W.2d 51, 55-56 (Iowa 1994). Nonetheless, we conclude that this case is distinguishable because Urban Dictionary allows for anonymous, user contributed content. Moreover, without any review of the definitions posted on Urban Dictionary, there is a substantial danger that the definitions will not be generally accepted. Therefore, the DMV's practice risks prohibiting words or phrases based on meanings that are not commonly known or recognized, even as slang terms.

An interesting — and, I think, correct — conclusion, and one that's relevant to other user-generated references such as Wikipedia. As I've noted before, for tangential and uncontroversial matters, Wikipedia may be quite good enough. Government employees' time isn't unlimited, and tracking down authoritative sources to demonstrate the colorfulness of Polish boxer Andrew Golota — to give an example from a Seventh Circuit case that cited Wikipedia to support such an assertion — is probably not the best ways to spend that time. But for something controversial and important, it seems to me that Wikipedia and other reader-generated sources that aren't edited by known and trustworthy authorities should not suffice.

Note that I'm not concerned here about outright lies and manipulations. It seems likely that people who contribute to the Urban Dictionary contribute usages that they themselves have observed. And in fact it's possible that "hoe" (and not just "ho") is seen by some or even many people as slang for "whore," unless some other meaning — say, gardening-related — is visible from context. But all the entry in the Urban Dictionary means (unless the court and I misunderstood the way the Dictionary works) is that one person has claimed that a word has a particular slang meaning, and that the site operators didn't block or remove the submission; it doesn't mean that anyone checked to see whether the definition is in fact common, rare, or even purely idiosyncratic with the submitter and his small circle of friends.