Syncthing is a cross-platform peer-to-peer file synchronization client/server application written in Go. Similar to BitTorrent Sync, the tool can be used to synchronize files between computers however, unlike BitTorrent Sync, Syncthing is open source
"Syncthing replaces Dropbox and BitTorrent Sync with something open, trustworthy and decentralized. Your data is your data alone and you deserve to choose where it is stored, if it is shared with some third party and how it's transmitted over the Internet".
Read the full thing at http://www.webupd8.org/2014/06/syncthing-open-source-bittorrent-sync.html