This approach seems to overlook the bigger picture which is that Dropbox makes sure it doesn't lose your data. Aside from that the web interface and dealing wit

This approach seems to overlook the bigger picture which is that Dropbox makes sure it doesn't lose your data. Aside from that the web interface and dealing with conflicts is an important issue. Just imitating the syncing is not going to cut it, and if you're not outsourcing the storage it rather defeats the purpose of not having to worry about the data anymore.