6. Also not clear is how much portability users will have. At this point they offer beta users a way to download the contents of their site. This doesn't make it possible to use it as an editorial system for other environments, or the other way around, to use other tools to author content for Medium. There's no doubt Ev understands the opportunities here. Blogger had a pretty complete API as did Twitter. But in Twitter, everyone got burned by the API, including the company (though to a much lesser extent than developers) so my guess is that Ev's new company will be more conservative about interfaces than his previous ventures.