You don't know many truly rich kids, do you? I mean really rich, not doctors kids, but actual multimillionaires kids. I knew them a bit and private paid social network would suit them well.
Just the term "rich kids" -- I doubt a rich kid would want to associate.
I hope they didn't spend too long writing the app -- well just to get this far, creating & launching the thing - that's not a fail. Hopefully they didn't outsource, though I suppose that's a skill too.
edit: Just to be clear - at one stage of my life I lived in a "millionaires" closed community, so I know from my own experience how the kids are. Not all but I would say it goes 50/50. 50% are empty and showing off, and rest are either quite normal or even ambitious.