The start-up, founded in 2013, boasted big name investors including Google's venture capital arm, Kleiner Perkins Caufield & Byers and partners from the incubator Y-Combinator. In total, it had raised $35m at an unknown valuation. Unusually, Mr Byttow said he was returning capital to investors.
Secret was part of a wave of anonymous sharing or chat apps that sold themselves as an alternative to identity based social networks such as Facebook and Twitter. Its rivals included YikYak, which has made a name for itself by focusing on college campuses, and Los Angeles-based Whisper.
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Even Facebook tried to experiment with anonymisation, in the belief that some users feel they can express more when they are unidentified, by launching the app Rooms last October. But Rooms, a theme-based site, did not take off.
"I believe in honest, open communication and creative expression, and anonymity is a great device to achieve it. But it's also the ultimate double-edged sword, which must be wielded with great respect and care," he said. "I look forward to seeing what others in this space do over time."
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Secret was founded by two ex-Googlers, Mr Byttow and Chrys Bader-Wechseler, and rose to prominence in Silicon Valley as tech company insiders began to use it to post rumours of forthcoming technology deals.
Posts to the app revealed the imminent departure of prominent Google executive Vic Gundotra and that Nike was shutting down its fitness tracking Fuelband unit.
But it also became popular for political discussions in Israel and Russia, and had formed a joint venture in China, where Facebook and Twitter are banned.
Anonymous apps have faced a challenge to strike the right balance between freedom of expression while combating abuse in their forums. For example, Whisper employs more than a hundred moderators who work to make sure no proper names are used on the platform or nude photos posted.