I’ve been doing this since 1999.
Discussions about scholarly blogging most often centre on the need for we academics to write in ways that attract new audiences. If we write blogs, we are told, we can communicate our research more effectively. Blogs enhance impact; they are a medium for public engagement. The advocacy goes on… Blogs (and other social media) can point readers to our (real) academic publications, particularly if they are held on open repositories. Blogging, it seems, is a kind of essential add-on to the usual academic writing and academic publication that we do.
Source: Pat Thompson, Seven reasons why blogging can make you a better academic writer