Filosync 1.0 Beta
Filosync is now in beta:So we’re working to deliver software that brings all the benefits of cloud computing without forcing you to hand off control to a third-party provider. Filosync’s flagship product runs in your own Amazon Web Services account, and all your data are encrypted with keys only you have access to. Or you can run the Filosync server on-premises for even more control over your data.
It sounds like a private version Dropbox. From Arq developer Stefan Reitshamer.
Update (2013-09-14): Filosync is now shipping.
