In a backlash against the Ivan Tribble nonsense, some academic bloggers have been trying to make the claim that blogging will help your career. I'm pretty skeptical of either claim; I suspect it is a wash.
As evidence that blogging doesn't help much, Dan Drezner was denied tenure last week. I can't claim to know the particulars, though I look at his CV, one would think a couple of books and two dozen papers would be good in Poli Sci. Regardless, since his blog is consistently in the number one position in the Truth Laid Bear Academy community, and in the top hundred blogs in the world, this would seem to be evidence that having a well-read and influential blog won't assure you tenure and promotion, at least at the University of Chicago.
Will U of C eventually regret its decision? It should ... but universities aren't really known for their introspection (we specialize in deep thinking about OTHER people). Should the untenured or unhired panic and delete their blogs? No ... but doubtless some will. Will Drezner land on his feet? You can bet the farm on it.