What is the causal impact of researchers reading blogs?

Again from the World Bank, here is a study of that question, with the blog in question being Development Impact.  Summary excerpt:

There are large impacts on dissemination of research; significant benefits in terms of the bloggers becoming better known and more respected within the profession; positive spillover effects for the bloggers’ institutions; and some evidence from our experiment that they may influence attitudes and knowledge among their readers. Blogs potentially have many impacts, and we are only measuring some of them, but the evidence we have suggests economics blogs are playing an important role in the profession.