Jimbo (Wikipedia) Wales guest-posts at Lawrence Lessig's blog
He is going down a list of "Ten things that will be free." Not should be free, but will be free. #2 is Curriculum.
Commentor Frank has a very good point - there's a financial incentive to produce non-free curricula. What's the incentive to produce free curricula? A sense of public service? A tiny bit of ego perhaps (but let's call it Mazlowvian self-actualization)?
This was echoed in a recent discussion on ITFORUM on the value that publishers add in the new world of online self-publishing. David Wiley made the point that the real value that publishers can bring is the process of editing and providing a structure for peer-review of content. (One might counter that that's the same argument made by the "MSM" against blogs, invoking the high and mighty system of "journalistic checks and balances.")
The main problem that I see is that without a well thought out compensation model, the quality of freely-produced content is going to be all over the map. As was pointed out in the comments, good writing and good illustrations matter a great deal and take time and effort. Where does this time and effort come from? Wikipedia is an interesting model of how people can and will contribute their spare time (and I've certainly done my bit), but the product that results is inconsistent.
How do you enforce a style sheet on unmanaged and unmanageable volunteers? Without a system of compensation, how do you make clear roles and expectations? If Expert A doesn't like the edits that Writer B makes to his ramblings, he can pack up his kit and go away, leaving an article - or a book - or an interactive multimedia program - high and dry. What then? Do we blithely assume that someone else with copious amounts of free time will just step in and pick up the pieces out of a sense of social contribution? That certainly seems to be the case.
Finally, I have to say that I find the political tone of some of the comments amusing, if not surprising. There seems to be an assumption that all forward-thinking educators drink from the same pool of social progressivism. Not so. Some of us are shockingly conservative in our worldview. :-)