It's interesting that the same month in which Wikipedia is reported to be in serious decline, an article highlights that in the US, the number of court opinions relying on or pointing readers to Wikipedia is exploding. In their article "Wikipedia in Court: When and How Citing Wikipedia and Other Consensus Websites is Appropriate", Jason Miller and Hannah Murray note that "Wikipedia" had 504 cites in the federal and state cases database on Lexis as of late 2009.

In Canada, courts haven't cited Wikipedia that frequently, but it is happening more and more. Canadian courts have cited Wikipedia to define such terms as "hedge", "trust", "shock jock" and "Thiru" (used as a password in a credit card fraud case). At least a couple of Canadian courts have been dismissive of Wikipedia as a source: "I am aware of the checkered reliability of this encyclopedia" (de Montigny J. in Moiseev v. Canada); "the use of information from the Wikipedia Web site is highly questionable" (Martineau J. in Fi v. Canada). But from what I could find, the only court to consider the reliability of Wikipedia at any length has been the trial court in a Quebec case, R. v. Cianfagna. Finding that a Wikipedia entry for "rubbing alcohol" was reliable, the judge considered that there had been many authors of the article, that there was little controversy evident from the history and discussion pages, and that the article was referenced. An appeal was allowed on other grounds, with the appeal court not commenting directly on the trial judge's citing of Wikipedia. 

So the question remains: when is citing Wikipedia in court decisions appropriate? Miller and Murray offer a helpful framework in their article. They propose that Wikipedia can be cited when it is appropriate to cite the wisdom of the crowd:

"The wisdom of the crowd is an appropriate and valuable reference when consensus itself is at issue, the information is generally known, or the content is easily verifiable."

The authors go on to give examples of how this principle applies to US cases that have cited Wikipedia. Good examples of where Wikipedia was cited include where the colloquial meaning of a phrase is at issue ("car accident"), to define a party's likely meaning of common industry words used in an email ("fabs"), or what the average consumer would believe a contract term meant ("business days"). The authors offer that citing Wikipedia is inappropriate where the information is of a technical nature such that it would only be reliable if the editor possessed specialized expertise, or where the editors/contributors are likely to be inflamed about an issue.

This framework appears to be a good one for making the best use of Wikipedia in legal research.