Maybe it's because I don't have an iPhone, or a smart phone, but I seriously don't understand instagram's insane adoption/appeal. It seems bizarre and not nove

Maybe it's because I don't have an iPhone, or a smart phone, but I seriously don't understand instagram's insane adoption/appeal. It seems bizarre and not novel in any way. Mobile sharing has been around forever, and even my 2005 feature phone has filters built into it. Someone enlighten me.