I like the idea. Here's a thought: There are a few sites out there which rate charities on where donated money goes. Research those and convert the percentages

I like the idea. Here's a thought: There are a few sites out there which rate charities on where donated money goes. Research those and convert the percentages into steps - for example, if you take 10000 steps a day, and your charity runs a 10% administration overhead, then your first 1000 steps go to the charity, the rest go to the people the charity should be helping (and if you are making profit from your app, tell them how many steps you guys are taking). This may help you with the motivation issues. I can't check your app as I'm an android user, but could you add a cooperative mode? Rather than compete against your friends, why not pool your steps together? Competition could be added to this through a co-op leaderboard. Also, lazy bastards like me could sponsor teams ('I'll give you $10 if you hit a million steps with your friends') This could open up interesting things like a whole company 'stepping' together, the you could have Google vs Facebook step contests for charity. Good luck on your venture!