OK, so it's not nearly as compelling as Neo-Nazis breathing hard outside the door, but I ran across this today on the "Excessive Sweating and Facial Blushing" site (it was linked from the talk page of another WP user):
A group with an agenda (opposition to a drastic type of surgery to treat sweating disorders) discovered Wikipedia, said, "hey, we can support our agenda there"...."but wait, they have an NPOV policy"...."that's ok, we can do that"..."in fact, let's invite the doctors who support the treatment to come work on it".... http://www.esfbchannel.com/cgi-bin/yabb/YaBB.pl?board=ETS_General&action...
And now, two months later, we have a fairly balanced little article on [[Endoscopic thoracic sympathectomy]], which the group is now telling other ETS/anti-ETS sites they can use and copy (WITH proper GFDL linking and credit, no less!): http://en.wikipedia.org/wiki/Endoscopic_thoracic_sympathectomy
Obviously these are rational people, and not ideologues of any stripe -- still, I thought it would be a nice bit of evidence that the system /does/ usually work. :)
Catherine