I've been using this little tool to produce documentation for my team. As soon as they get more intelligent response replay in I think it will be a winner.
Until then it's still a pretty damn good web service centric markdown editor.
Maybe this isn't what he's talking about but it would be really cool if there was an easy way to test your API implementation with example requests in your documentation.
This is available as closed alpha, but we working hard on extending this functionality to be actually usable (read: scenarios, because you usually need to do at least some sort of "setUp").
Until then it's still a pretty damn good web service centric markdown editor.