ChronoShare provides services similar to Dropbox, but in a decentralized way.
It uses ChronoSync library to synchronize the operations to the shared-folder and levels NDN's advantage of natural multicast support. The sharing process is completely decentralized, but it is also very easy to add a permanent storage server.
ChronoShare also provides file history and basic version control.
To see more details about ChronoShare design, click here.