Since Dave is in the mode of making desktop versions of his apps, I would like to make the case for Electric Outline, or in other words an Electron version of Little Outliner. 

For some reason a desktop version of LO seems to make a lot of sense to me, probably because the documents I create in LO are private. The downside, however, is that if local file storage is used then my outlines would not be accessible from other devices. 

An approach might be a variation of the privateFiles and publicFiles structure nodestorage uses for 1999, but for a desktop version it would work slightly different. PrivateFiles would map to a local folder while publicFiles would map to a S3 bucket. Any file stored in publicFiles can be accessed via Electric Outline running on any computer so long as it has the credentials to access the S3 bucket. 

I think the result would be the perfect combination of keeping files local for privacy and security while providing a way for OPML files to be shared publicly.