I really love Trello, I think I could use it in so many facets of my life...but the nonstatements on its future (is it going to be monetized? is it even going to be around in six months? etc.) make me hesitant to really commit to it.
Edit: https://trello.com/privacy states the above clearly, near the bottom. I agree that slapping that under the "Privacy" page probably doesn't make sense.
(I work for Fog Creek; go through my comment history.)
However you raise a good point: exportability/portability of the data...
Disclaimer: I'm a developer on Trello.
But unless you're expecting only developers/programmers to use Trello, then saying "using the Trello API or just by appending '.json' to pretty much any URL" is basically worthless to most people. Our definitions of "very easily" must be enormously different.
I mention that because a vastly saner export tool that's highly newbie-friendly is outlined at https://trello.com/card/bulk-data-export-for-organizations/4...