Secret raised their B last July at a post valuation just over 130M (http://i.imgur.com/jNXw5PZ.png). They had some major investors backing them up, and then the hype train just... stopped.
I remember so many people being so high on it when it launched, with several friends all raving about how fun/addicting it was, then just poof it disappeared from conversation.
Hearing that the founders got some cash off the table (article from last summer - http://www.businessinsider.com/secret-founders-pocket-6-mill...). While I always thought that seems like a good thing, I can't help but let my mind wander a bit as I know if I were given a nice chunk of change like that so early, it might be kind of hard to keep focus.