Rob Jenkins has an interesting piece at the Chronicle of Higher Ed on whether blog posts ought to count more for tenure. I'm a big fan of academic blogs, and I think outlets like The Monkey Cage and all the others linked to the right are important for disseminating knowledge.
But blogs are not peer-reviewed, and so they should not count (for much) when it comes to tenure decisions.
Tenure exists to solve a problem. It might not be the best or only solution, but it should be understood for what it is. That problem is ultimately that you want the material that is being taught in your classes to be what the experts in the discipline say is correct, and not what some political, religious or ideological leadership thinks.
Problem: Who is in charge here?
I teach at Georgetown, an at least nominally Jesuit institution. I lecture on abortion politics in my political parties class. My students would like to believe that what I tell them is what the scholarship says, and not what the Pope might like me to say about abortion. The same goes for any articles I write, public lectures I give, and even this blog. Fortunately, Georgetown takes scholarship seriously, and makes no effort to control course content in this way. But the idea is not unheard of. We don't want schools to fire academics when their research findings turn out to be unpopular.
Solution: Academic freedom
So, how do we solve this problem? We prevent Georgetown from firing me over the content of my teaching or research. I can be fired for neglecting my job, or other misconduct. Tenure is not the same thing as lifetime employment. But a tenured professor shouldn't be fired for teaching material within their area of expertise, even if their administration or other political superiors disagree with it. The only constraint I have on my publishing is the peer review process.
Problem: Who is an expert?
Problem solved. Give faculty academic freedom and they won't feel beholden to the opinions of their employers. But that just creates a bigger problem. How is the university (and by extension, my students, or you, gentle reader) to trust me when I say that these are the things that my discipline says are correct or important? I am supposed to know better than the president or the trustees, at least when it comes to American political parties. But if I know better, who can judge me?
The answer is, my colleagues, both in my department, and more importantly, across the discipline. When I started here, I had a Ph.D., which at least guaranteed that I met some minimal standards of expertise. But that was the probationary period. For tenure, the university compiles a comprehensive file on the candidate's accomplishments, including most importantly, letters from outside experts, who can vouch for the candidate's contribution. Tenure decisions are based on all that information about whether or not the candidate knows what they are talking about.
What does this say about what kinds of things should "count" for tenure? It says that what counts are those things that indicate expertise in the field. A blog does not indicate expertise. Anyone with a computer connection can write a blog. (We know.) This is also why teaching is not as important as research. Someone who knows just a little bit about a subject can get good course evaluations if they make their class entertaining enough. Interviews with the media don't count for much, either, because journalists aren't always the best judge of who is really an expert. Peer-reviewed publications are the best things we have to provide information about expertise.
In short, tenure gives you a platform, and some protections in how you use it. But you can't use the fact that people do listen to you to decide whether or not they should. If you say something that is true but unpopular, we don't want you to lose that platform.
Of course, there is a lot of mission creep with tenure. If you're going to make it hard to fire someone, you might want to make sure that they are not only an expert, but also good at their job. Are they good in the classroom? Are they good departmental and university citizens? For these questions, contributions like blogs do matter, in a very small way. Which is why these other things generally count for something in tenure cases, just not very much.
And there are plenty of problems and perverse incentives with the peer review process. But if blogging solves those problems, we need a better argument than just saying that what is widely read is best. Proposals to reform tenure should not lose sight of what tenure is for.