I'm glad to see a few #indieweb people building on OPML. There's a lot you can do with it. For example, the native file format of LO2 is OPML. So it's really good for editing subscription lists for feed readers. And editing blogrolls. My listicle tool takes OPML files as input. And River6, coming soon, does a bunch with OPML. There's also feedBase which will blow your mind if you love sharing subscription lists. Yes there's a lot to discover in OPML-land and more on the way.
I should write a howto to explain editing subscription lists in LO2. I wrote one for the OPML Editor in 2008. It still runs btw, I use it, sometimes even to edit subscription lists. Two key bits for LO2: 1. You can make outlines public. Look in the File menu. 2. And you can edit the attributes of a headline, click the suitcase icon in the left margin.
Some interesting tidbits to poke into here.