Also,
I love this post on why people (women especially) don't edit:
http://suegardner.org/2011/02/19/nine-reasons-why-women-dont-edit-wikipedia-...
And this post on the motivations of active editors, well-compiled by Steven and Maryana:
http://commons.wikimedia.org/w/index.php?title=File%3AWikimaniaMotivationsTa...
Do we have any good data on what motivates people to make their *first* edit?
Jake