On my Android phone I've setup btsync to to share documents, photos, music, pictures, etc. I no longer need to hook up my phone to the computer and manually initiate a transfer of data in either direction. The phone is simply backed up, and if I want to get rid of stuff on the phone, I can just get rid of it in the shared (mirrored) directory on my computer, and with the next sync, my phone is cleaned, too.