This seems to be an actual case of the begging the question fallacy. Why someone writes a blog is very personal. If, and only if, you are writing a blog for

This seems to be an actual case of the begging the question fallacy. Why someone writes a blog is very personal. If, and only if, you are writing a blog for lots of people to read it, then you do need to ask yourself if lots of people are reading your blog, and if not, what you're going to do about it. There are lots of reasons why someone might keep a blog (as many posters here demonstrate), the simplest being "because they want to".