OmniOutliner (iPad & Mac) is getting left behind in an ecosystem in which Markdown outlines have become a common currency of exchange.

Markdown outlines (nested hashes + use of tabs for additional level of ordered or unordered list indentation) have two advantages over OPML:

1. Read and supported by a wider range of tools, and
2. have a richer data model - support bold, italic, labelled links and the MMD extensions.

They can also, with @key(value) tags in the Taskpaper/Foldingtext idiom, support the equivalent of OO's additional columns.

OO needs to be able, on OS X & iOS, to:

1. Read MD outlines with Taskpaper @key(value) tags
2. Save MD outlines with Taskpaper @key(value) tags

Thanks !

Rob