What, really, is a blog? A kind of writing? A format? A genre?
In the years since the first blogs, we've seen how blogging has spread and changed to encompass a wide range of writing: business blogging, mommy blogging, fashion blogging, sports blogging—etc. etc. It's as consequential as the printing press; the press didn't create the book, but it did enable the spread of books. Similarly, the web wasn't built on blogs, but blogging sure has enabled the web to grow rapidly.