University presses are sufficiently important to historical scholarship and enough of them have now established blogs that we've set up a separate category of them on Cliopatria's History Blogroll. So far, they include:
Insofar as they can avoid merely being outlets for press releases, university press blogs can be of interest if they post links to significant reviews of their books and encourage authors of their books to engage with readers on the blogs.
Beyond that, university presses can best take advantage of blogging by making their books available to bloggers for reviews. The Valve's book event on Michael Bérubé's What's Liberal About the Liberal Arts? is a model of what can happen. Just check it out via Google or Technorati. Btw, Michael, I owe you a review.