Mark Goodacre just posted his thoughts on this at his ntgateway.com/weblog. He is basically responding to someone who thinks that academic blogging should have little to no affect on tenure decision. Goodacre thinks it can be a useful factor if the blog is a reasonable service to others and a successful way of getting criticism and feedback on one’s work in a webworld kind of way.
Goodacre hints that he thinks academic blogging could also give a boost to a student applying for a PHD – it shows enthusiasm, and (I think) a bit of networking. If a professor can go look at your blog (which is on your resume or application), she can learn loads more about you than the application form shows – this could be very good if your blog is both interesting and critically engaging. So for those who blog on academic things (reviews, latest issues, discussions, etc…), your blog may be doing good for you in ways you had not thought about.
Now I think Goodacre is being progressive in a way that many professors (and I fear many Brits) don’t especially get excited about. But, for those who do understand the help that blogs are to others (and oneself), it is surely a boon.
Of course Goodacre would think of blogs as a helpful factor for tenure, being the grandmaster of biblioblogs, but I think he has a good point.