Excellent question and this is on our roadmap (yes, I know, vapourware until we ship it). The plan is to export as HTML with standard microdata annotations (th

Excellent question and this is on our roadmap (yes, I know, vapourware until we ship it). The plan is to export as HTML with standard microdata annotations (the same we use to automatically import). That should be fairly durable, as far as formats go, and even if the HTML dies at least it is structured (for conversion to a new format) and text-based (at worst you can still read the source).