http://punkrockor.wordpress.com/2014/08/26/academic-blogs-a-labor-of-love/
The vast majority of academics I know do not blog, but I wouldn't use this article to imply they aren't passionate about their work. Mostly, I think they don't blog or use social media in a professional fashion because there aren't norms and incentives for them to do so. That is gradually changing, and as more people find that blogging and social media use benefits their own work, more will engage and become examples for others to follow.
The vast majority of academics I know do not blog, but I wouldn't use this article to imply they aren't passionate about their work. Mostly, I think they don't blog or use social media in a professional fashion because there aren't norms and incentives for them to do so. That is gradually changing, and as more people find that blogging and social media use benefits their own work, more will engage and become examples for others to follow.