I use wikipedia quite a bit and would trust it just about as much as I
would trust anything else, i.e. with a fair degree of scepticism. I
try to judge from the general style and standard of the article, and
if the information is important to me I would always try to find a
corroborating source. At least errors in wikipedia are easy to fix.
Dead tree sources may as well be tablets of stone when it comes to
correction, and even blunders on non-wiki websites can be difficult to
get corrected.

I have corrected errors in wikipedia on a number of occasions - always
things that are clearly wrong and easy to correct - I have not written
any substantial pieces of text myself. And I would strongly urge
others to make corrections. It annoys me when I read someone
complaining in some forum or other about specific errors in wikipedia,
when they could have fixed the article themselves in less time than it
took them to complain.

--
Steve Slatcher
http://pobox.com/~steve.slatcher