I wanted to build something like this - basically a P2P based End-to-End encryption messaging technology (so it doesn't get inspected by peers) for use cases such as messaging (a-la SMS) on a non-networked environment such as cruise ships / National Parks, etc [maybe through bluetooth or something]. Cruise lines should / could easily build a messaging app that works on a closed network (lots of branding potential.. not sure why it hasn't been done yet!). If anyone is interested ping me. :)