What changes is the knowledge that comes from viewing a different perspective on the fact at hand.
I haven't used Wikipedia that much and when I have used it I have found some of the information to be (from my perspective) incorrect. Some things can be stated with a fair degree of certainty. Others require some perspective in order to be better understood. Wikipedia provides a forum for presenting this alternative perspective.
But, as so many posts have said, to accept only one perspective as the definitive truth is.. well, what can I say... stupid.