I have noticed my "word count" posts tend to get lots of positive feedback. I guess people are happy with my progress or showing support.
I think that once you've got someone reading your blog that kind of post is something they'd like to read. They're happy to hear you're doing well and that your novel is coming along fine. It's a little bit of positivity and through being readers of your blog they're sort of sharing in your success - it makes them feel good.
The trick then would be to get them to start reading it in the first place which may require different kinds of posts.