git-annex can already be used to store data in several cloud services:
Amazon S3, rsync.net, Tahoe-LAFS, The Internet Archive.

I would like to support as many other cloud services as possible/reasonable.

* [[swift|todo/wishlist:_swift_backend]]
* Dropbox (I had been reluctant to go there due to it using a non-free client,
  which I have no interest in installing, but there is actually an API,
  and already a
  [haskell module to use it](http://hackage.haskell.org/package/dropbox-sdk).
  Would need to register for an API key.
  <http://www.dropbox.com/developers/start/core>.
  Annoyingly, Dropbox reviews each app before granting it production status.
  Whoops my interest level dropped by 99%.)

Post others in the comments. --[[Joey]]