Seriously? I know there was once a study that compared Wikipedia to Britanica, and it scored well, but I really think this is a bad idea to give Wikipedia quite so much credibility.
I mean, in truth, it really speaks to how much people use Wikipedia, and how much it has become a cultural icon, more than its reliability as a source. I mean - people are simply using it, therefore people are going to use it. Bit of a self-validation thing.
Anyway, yeah, this is a smart feature to include in MS Office, and mega-props to the Wikipedia team both for quality of content and for becoming such a defining iconic institution.
Still, I can't help feel like this is a bad idea.