timmmay: I see many advantages, though what do you do when an internet connection is down and people don't have a smartphone to email you with? I guess they have to go to a neighbour or internet cafe?

Our target market has smart phones (you probably wouldn't sign up if you don't have one), but yes if they really can't get online that way there are neighbors, Internet cafés, normal cafés, mcdonalds, spark phone boxes, libraries, work, uni, bars, and many other places where internet connections can be had, usually for free.