The Times is hosting an interesting forum on the gender gap among Wikipedia's contributors. I found Justine Cassell's contribution pretty interesting:

As for the source of the gender imbalance, I think it may be revealed if we compare what Wikipedia looks like from the outside vs. what it looks like to a contributor. To those of us who don't spend time contributing, it does indeed look like Wikipedia is a democracy of knowledge -- a place where all we know is gathered together and made available to all of us equally. ho wouldn't want to be involved in such a lofty enterprise? 

From the inside, on the other hand, Wikipedia may feel like a fight to get one's voice heard. One gets a sense of this insider view from looking at the "talk page" of many articles, which rather than seeming like collaborations around the construction of knowledge, are full of descriptions of "edit-warring" -- where successive editors try to cancel each others' contributions out -- and bitter, contentious arguments about the accuracy of conflicting points of view. Flickr users don't remove each others' photos. Youtube videos inspire passionate debate, but one's contributions are not erased. 

Despite Wikipedia's stated principle of the need to maintain a neutral point of view, the reality is that it is not enough to "know something" about friendship bracelets or "Sex and the City." To have one's words listened to on Wikipedia, often one must have to debate, defend, and insist that one's point of view is the only valid one...

However, it is still the case in American society that debate, contention, and vigorous defense of one's position is often still seen as a male stance, and women's use of these speech styles can call forth negative evaluations. Women may be negatively judged for speaking their mind in clear ways and defending their position. A woman who wishes to collaboratively construct knowledge and share it with others might not choose to do so as part of a forum where engaging in debate and deleting others' words is key.

It seems to me that is not just a Wikipedia problem,  but a societal problem likely extending out from families and schools. Defending your words strikes me as a really good thing. Dissuading women from doing that strikes me as just the opposite.

That said, I'm not convinced that there's nothing that can be done. For whatever reason, I think Internet sites that allow trolling and aimless idiocy to run roughshod have a disproportionate effect on women. (Terri Oda hints at exactly that here.)  I don't know if that's because trolls and idiots are more likely to say something sexist or what. But I don't think the problem is aggressive argumentation, so much as its weak people saying these behind a cloak of anonymity which they'd never say publicly.

In World of Warcraft, I almost never talk in the public channels as they seem to be a haven for racists. When Matt was here, and before I was actually blogging, I was often tempted to comment. But it seemed that whenever a social science post came through, no matter how well written, in comments, it eventually came down to black people having smaller brains. Or some such. Enforcing strong standards in comments is a kind of general value that, I think, has specific impact on women and others.

I don't know that this sort of control is even possible with Wikipedia, or ultimately desirable. It also has says some downsides. It necessarily shrinks the realm of debate. It's always open to abuse by moderators. The intelligence of those who have something to say, but simply lack the requisite social skills to say it respectfully, is lost.

Finally there's the fact that diversification of contributors, means diversification of demands. You are no longer at the bar with your boys any more. Incorporating women voices isn't just a matter of getting a bunch of people with a different make-up of chromosomes to nod along. It's a matter of opening yourself to people who, fairly regularly, will dispute what you have to say, in ways that, initially at least, don't even seem credible to you. But often the most interesting lines of attack are the ones that seem preposterous at first glance, and yet stick with you. For my money, that's the real "strong debate"--one that occurs along lines that you don't simply disagree with, but that you've never even bothered to consider.

In effect you trade one group of critics for another.  Which is fine. I'm kind of sick of dudes who are "internet-smart." At least the fucking feminists are interesting.