I built exactly this app (functionally, but even used "down" in our vocab) in 2003 for a class project called Nitester using the web and an AIM bot. If only I had the drive then to push it further rather than jump to the next project :/
Do you seriously think a web based, AIM bot from 2003 is "exactly the same app" as a mobile, iOS, push notification based app of 2016? Your takeaway from this shouldn't be thinking you would have succeeded if you had the drive and kept working on it. There are probably at least tens of thousands of other people who tried solving the same problem, counting myself. I honestly have no idea how this took off because I've seen so many apps that tried to do the same thing and never took off, but these guys did. So I give them credit for the execution.
I actually had never seen anyone do anything quite like it since until now -- what are these other ones?
Social is very tricky -- network effect is everything, and the founders ability to time and push that out is a combo of luck and skill. Just looking at the history of chat services is a clear demonstration of that.
Thus I'm not saying nitester was guaranteed to be successful, but the concept was the same, the context was good (I was in college and Facebook didn't exist yet so social was open), and I had the friend networks and already threw big parties/raves. I just regret not giving it a bigger shot. It did help me get into MIT for grad school so at least something good came out of my laziness :)