One maybe slightly odd piece of advice: travel. Go out there and see experience how other people live. Because the whole 75 mile radius thing suggests to me th

One maybe slightly odd piece of advice: travel. Go out there and see experience how other people live. Because the whole 75 mile radius thing suggests to me that you a limited view of the world. That distance has very different meaning in many places, depending on population density, culture, transportation etc. "Near" and "far" are not universal constants, and understanding that was pretty central to your app. There are many other variables like that, many of which are especially relevant to both mobile apps and social networking, both of which are heavily influenced by context.