Any time you build a network, you have to help users find their friends.
Frankly, the hardest pieces of feedback we got in the U.S. was, 'I would love if more of our friends were on Path. It's hard to get them to join.'
I have two iPhones: one for day and one for the night. When the day phone runs out, the night phone takes over. I never have to worry.
In mobile, people really love having single-use case experiences. They want low friction to getting to the application's use case.
In social, you have to innovate in information. If you have the same thing as everyone else, you're just not interesting.