This seems to be the media lab's "PubPub" platform. Interesting UI. Comments get a far greater role, presenting them on the right hand side and linking them to highlights. There's a revision history, too. Not sure who would want to read prior revisions of a blog post.

See: http://jods.mitpress.mit.edu/pub/design-as-participation

It's good to see a slick blog site to accompany their publication.