John Holbo and Belle Waring of Crooked Timber have written a new introductory textbook on three of Plato's dialogues. In addition to issuing a cheap paperback, they've made the entire book free in two formats: full-screen internet-based flashbook (with animations!), and as a downloadable pdf (download option available at previous link). The authors encourage university instructors to assign the book in their classes, and offer best price -- free -- as an incentive. I've skimmed through it, and it is very good, although I'm not qualified to judge its appropriateness for an introductory philosophy or political theory class.
In any case, I applaud Holbo and Waring for making their work available at zero cost. As does Matthew Yglesias, who says the following:
But it’s definitely true that more academics should be doing this sort of thing—it makes sense for people who are paid to add to the stock of human knowledge to be doing as much as possible to disseminate said knowledge.
Maybe they should and maybe they shouldn't, but it's a strange question coming from Yglesias. After all, he is also paid to "add to the stock of human knowledge," and he too has written a book to "disseminate said knowledge". As far as I know, Yglesias does not give that book away for free in any form.
And yes, Yglesias disseminates knowledge for free on his blog, but so do Holbo and Waring. So why should academics be held to a higher standard than pundits?