I also released outlineBrowser. It does for JSON outlines what riverBrowser does for rivers. The two are a pair, because outlines can appear in rivers, you need both to display a river. I wanted to separate them, however, because outlines can appear outside of rivers.
I have tons of content in this format. Frontier, OPML Editor and Fargo outlines are all stored in OPML. It's the standard format for RSS subscription lists. There's a lot of OPML out there. And PagePark should be able to do a nice job with all of it.
Slowly and surely it's coming together.
PS: Here's a short demo of an outline in a river.