These developers are riding the same wave that carried BitTorrent Sync, a file-syncing system similar to Dropbox but heavily encrypted and without a central server. Sync now counts more than 2 million users only 16 months after launching.
The growth of Sync apps is in the early, fragile stages. None of the software is even at the so-called "beta" stage of development, where wider testing can begin. And all of the apps could be scuttled by one false move at BitTorrent Inc., the file-sharing company that developed Sync and controls the platform interfaces on which Sync developers build.