The Anti-Social Club is a social network that I built with a friend of mine, Arthur, with marketing and testing help from another friend, Liam. We built it in about two months, and released on both Android and iOS.
The main goal of the app was to offer an anonymous message/image board for the students at our university, UB. Membership was strictly enforced - I spent a bit of time programming a system that verified that a user was actually a student, based on their UB email address. Even faculty with a UB email would not be granted membership by the system. This gave us a huge advantage over our competition, Yik Yak, as you could be fairly certain that every user was a student.
Unfortunately, we shut down the Anti-Social Club about a month after launching it. Yik Yak released a very unexpected major update on our release day, and stole the spotlight from us. Suddenly, our new features and a promise of a fresh message board just wasn't enough to keep user retention up. The problem that we had created the app to combat had suddenly disappeared. Without enough money to keep the servers running, or time to work on adding new features, we had no choice but to shut it down.