Henry Farrell writes at Crooked Timber about the academic blog wiki he started that is now going to be kept up by the Center for History and New Media. I agree with the following:
However, as best as I can tell from personal browsing, academic blogs appear to be relatively robust. It’s a lot harder than it was nine years ago to create an academic blog that can attract substantial public attention, but if you’re primarily interested in talking to other academics and a few interested bystanders, it’s still relatively easy. Academic blogs, unlike e.g. tech blogs or some political opinion blogs, don’t usually have sufficient potential audience to become commercially viable. But most academics are used to talking to smaller audiences, and as long as blogging technology is cheap or free, there will be some people at least who’ll be interested in doing it.
Just like Fidel Castro and the Concertación in Chile, the death of blogs has been predicted for a long time but hasn't yet happened. After more than six years, I'm still really enjoying and deriving a lot of benefits from it, and in fact UNC Charlotte is working to encourage more faculty to use social media, including but not limited to blogs. Blogs will likely persist as long as there are professors (and now more graduate students as well) interested in using short form writing to discuss their research interests and/or current events.
So when the death cart comes around, don't put blogs on it yet.