That's the title of a longish, well-argued, very readable piece by Aaron Swartz, the highlight for me being a conclusion he arrived at by mining the data:
When you put it all together, the story become clear: an outsider makes one edit to add a chunk of information, then insiders make several edits tweaking and reformatting it. In addition, insiders rack up thousands of edits doing things like changing the name of a category across the entire site -- the kind of thing only insiders deeply care about. As a result, insiders account for the vast majority of the edits. But it's the outsiders who provide nearly all of the content.
(My emphasis). This contrasts with the results of some shallower research done by Jimbo Wales, and this kind of thing is why I for one would like to see Aaron on the Wikipedia board (although I couldn't vote because I've done <400 edits).Â@en