Fantastic!  I hope it allows rollback to an earlier version of the entire filesystem, too.  I know people who have lost large amounts of data on Dropbox because some client-side issue (malware or just plain error) deleted everything.  I think they also had some online backup service that could roll back files but only if the file was still there, which is useless.<p>Will you also support deduplication (files, blocks, context-aware blocks, or otherwise)?