I think it would be great if digital cameras had a Personal Area Network function; so, when you take a photo, you could instantly share it to all other cameras; no clicks needed.
The cool thing would be like this: You set up your camera on sharing mode and set it up as a server, then, other clients connect to yours automatically. Then, the server camera would take pictures and transmit copies to the other cameras, which could, in turn, serve the pictures and sync with the other ones.
I hope to see this function on cameras soon.