I know I'm getting old and set in my ways because it annoys me when people use "blog" to mean "blog post" or "article", as in "i wrote a blog today".
Given that "blog" is short for "weblog", as in "web logbook", you cannot write a blog in a day. You run a blog, or maintain a blog, or write it over time. Not in one day, no.
But that's just me resisting the inevitable evolution of language. Like an old person. Blergh.