You call this blog a blog because 15 years ago today, a guy named Jorn Barger coined the phrase "weblog". The term wasn't shortened to "blog" until two years later when another early online writer, Peter Merholz, jokingly listed it as "we blog" on the sidebar of his own site.
Barger's earliest posts are still all online, dating back to this day in 1997. It entered our collective vocabularies once Blogger launched and anyone with a little internet know-how could start broadcasting his or her thoughts into the digital abyss. But Barger was the first. So I suppose even we hacks have him to thank for giving a name to what we do. [RobotWisdom — h/t @waxpancake]