I find Wikipedia quite useful, in the proper context, chiefly when I'm trying to find out about (1) something that's not terribly controversial, so the risk of Wikipedia error or spin is likely lower, (2) and — more importantly — something that's not very important to my work, so the cost of possible Wikipedia error is lower. We rely on plenty of less reliable information under those circumstances; for instance, we might rely on our own recollections' of partly forgotten sources, or conversations with friends. There's no reason to categorically disqualify Wikipedia in those situations.

On the other hand, some uses of Wikipedia strike me as unsound. Consider this, from a law review article:

The history of the concept of "responsibility to protect" [FN1] sounds almost like a fairy tale. The International Commission on Intervention and State Sovereignty developed this concept in its 2001 report The Responsibility to Protect.... In December 2004, this idea was taken up in the context of the debate on United Nations reform.... In March 2005, this finding was endorsed by the report of the UN secretary-general .... [More historical details omitted. -EV]

Not long ago, the notion of "responsibility to protect" was added as a key word to the Wikipedia Free Encyclopedia, where it is defined as a recently developed concept in international relations that aims at "provid[ing] a legal and ethical basis for 'humanitarian intervention.'"

The articulation of the concept of responsibility to protect is a remarkable achievement.

The seeming success of the movement to recognize a responsibility to protect may well be a remarkable achievement generally — but having something "added as a key word to the Wikipedia Free Encyclopedia" is not a remarkable achievement: It can be done by one person anywhere in the world, with a modest investment of effort. It's even less of an achievement than being nominated for a Nobel Peace Prize.

Note also how the passive voice (another thing that I've defended, when it's used in the proper context) hides the unsound argument. The notion of responsibility "was added" to Wikipedia, the article says. But who did the adding? Some unknown and unscreened contributor.

Recasting the sentence in the active voice, as "Not long ago, a Wikipedia contributor added the notion of 'responsibility to protect' as a key word to Wikipedia," would have exposed the error. The passive voice conceals the error, especially to readers who don't fully understood how Wikipedia works. (And even if the author himself didn't fully understood how Wikipedia works, trying to recast the sentence in the active voice might have led him to figure the matter out.)