On Thu, 13 Sep 2007, Thomas Dalton wrote:
Wikis are, by Wikipaedia's own definition, self-published and therefore unreliable, especially when it comes to negative info on living persons.
For the main namespace, certainly. Other namespaces and the official logs are acceptable primary sources for things to do with Wikipedia and events that happened on it.
If I wrote on my blog that you eat hobbits, my blog is a primary source for "Ken claims Mr. Dalton eats hobbits", but an unreliable self-published source for "Mr. Dalton actually does eat hobbits". The former is an event that happened on my blog. The latter is unreliable info about a living person.
Most people who Google someone's name and come across a Wikipedia page about them will be using Wikipedia as a source in the latter, unreliable, way.