The social media app that popularized disappearing messages in 2011 was Snapchat.
Snapchat began as an iOS app called Picaboo, launched in July 2011 by Stanford students Evan Spiegel, Bobby Murphy, and Reggie Brown. It was relaunched under the name Snapchat in September 2011. Its defining idea was that photos, called Snaps, could be viewed for a limited time before becoming inaccessible, creating a more temporary style of online communication.
The app's disappearing-photo concept helped distinguish it from Facebook and other services built around permanent profiles and archives. Snapchat later expanded with video Snaps, Stories that lasted 24 hours, filters, lenses, chat, and augmented-reality tools. “Disappearing” did not mean perfectly private: recipients could take screenshots, and Snapchat has faced privacy scrutiny over how long data could remain accessible. Telegram, WhatsApp, and Instagram later offered related ephemeral features, but Snapchat popularized the format.