Wikipedia's list of blog types includes educational blogs (students and teachers talking about a course), but research and scholarship is another essential ingredient of higher education. There is no "research blog" category defined and it is difficult if impossible to find any historians or humanities scholars talking about their work in a blog, but this may change in the future.
The closest category to a general "research blog" is the "science blog" which is becoming increasingly popular in the science research community. There are issues though:
"...Individual scientists have received the idea of blogging with mixed feelings: while some see it as an excellent new way to disseminate and discuss data, others have expressed concern about potential damage to their credibility and plundering of their intellectual property. However, a number of scientific publishers have recently begun to embrace blogging as a means of promoting discussion."
Lack of peer review is also an issue. As more history scholarship makes it into online repositories and journals, intellectual property theft of ideas will become less of an issue since a simple Google search will reveal the plagiarism.
I used to be a contributing editor at Lambda the Ultimate, a computer science blog devoted to discussion on programming language research run by a computer science professor in Israel. Most computer science research papers make it to the web, so it's not difficult to keep his blog going. Since computer scientists have to be very focused in their research to make contributions they often lose touch with developments in nearby specialties that could be relevant to their own research. Blogs like Lambda the Ultimate help them broaden their perspective a little.
As important historical sources like the Ming Shi-lu make their way online or the Si Ku Quan Shu [Qing Imperial Library or "Complete Library in the Four Branches of Literature" compiled between 1772-1787][Internet Public Library], the web will probably increase as a publishing platform for historical research also.