"A blog is a text file on a screen. There's really no need to do it on a proprietary system, you can literally upload a text file to your own host, but if you can't be bothered, somewhere like GitHub Pages.

You want an image? Here's a tag: <img>"

Don't be surprised if someone has this "idea" soon and makes a killing with it. A lot of people seem to get tired with the current stream of "innovation" that makes the web slower and more complex.