[viennacoder]

I would do a mobile app that focused on privacy and photo rights. Kind of similar to apple's photo stream, but something that works on android too.

If you can include some sort of messaging functionality (like whatsapp) that would be good. The integration of photos and messages would need to be elegant though.

Mobile is facebook's Achilles heel.

It's a really hard space to break into. The odds are against you.