My latest Make: column, "Shortcut to Omniscience," talks about the cognitive shift that Wikipedians undergo in order to collaboratively write an encyclopedia, and how that kind of fundamental, subtle change enables networked groups of people to do things that were previously considered impossible.
Here's the thing about expertise: it's hard to define. It may be
possible for a small group of relatively homogenous people to agree on
who is and isn't an expert, but getting millions of people to do so is
practically impossible. The Britannica uses a learned editorial board to
decide who will write its entries and who will review them.
Wikipedia turns this on its head by saying, essentially, *Anyone can
write our entries but those entries should consist of material cited
from reliable sources.* While the Britannica says, *These facts are
true*, Wikipedia says, *It is true that these facts were reported by
these sources*. The Britannica contains facts, Wikipedia contains facts