[Fnoord]

They think they want, but they don't.

For every human being on the planet needs their own privacy. Its a common theme in the EU, but it isn't only important within the EU.

Therefore, there are two viable options:

1) You store your data locally (encrypted if you want to protect against burglars).

2) You store your data remotely, but encrypt it before you send it and decrypt it after you receive it (public key cryptography).

There is no other, viable, long-term option. Dropbox's solution is a short term solution.

Now, the question is whether you really need to sync to your LAN right away. You most likely don't. You can just sync in the evening and at night while your device(s) recharge. If you really need to sync ad hoc you have the option to punch holes in your firewall, or use a VPN. One opportunity for innovation here is to allow a user to define what must be synced right away over WAN and what shouldn't. Another opportunity is to make cloud backups easier. But these require the above requirement #2, and as you might know, public key cryptography just doesn't seem to be user-friendly.