The editor is very nice. Very simple. I think I understand what it is.
1. It's a blogging community.
2. It does categorization, but does it upside-down. Instead of adding a category to a post, you add a post to a category. Maybe a little like Delicious, but with an editor. I never was a big user of Delicious so it's hard to say.
3. It's very bare-bones. But like I said it's nice. :-)
And I appreciate the chance to try it out.
Here's a screen shot of the About dialog for the river. I thought I might use it for the picture in my Medium post, but it wasn't the right shape. Neither was the one I used. I think it's really designed for photos.