Having written both myself, this is totally absurd. The academy exists to teach people how to think critically and express those thoughts in a clear, nuanced way. Blogs exist to persuade and convince through rhetorical force. Clear and nuanced arguments can contribute to this end, but rarely constitute the core of a post. From the article:

Because, say defenders of rigorous writing, the brief, sometimes personally expressive blog post fails sorely to teach key aspects of thinking and writing. They argue that the old format was less about how Sherman got to the sea and more about how the writer organized the points, fashioned an argument, showed grasp of substance and proof of its origin. Its rigidity wasn’t punishment but pedagogy.

Exactly right (aside from the strange reference to Sherman, which doesn’t make sense even in the full context of the article). But there’s no reason blogs and papers can’t coexist. From a professor at Standford:

Professor Lunsford is playing to student passions. Her writing class for second-year students, a requirement at Stanford, used to revolve around a paper constructed over the entire term. Now, the students start by writing a 15-page paper on a particular subject in the first few weeks. Once that’s done, they use the ideas in it to build blogs, Web sites, and PowerPoint and audio and oral presentations. The students often find their ideas much more crystallized after expressing them with new media, she says, and then, most startling, they plead to revise their essays.

I like this approach, which helps to ensure that the arguments being made in those blogs and tweets are well-considered. But, then, I didn’t compose a 5-page paper before writing this post, so I could be wrong…