Facebook on Friday released the “poke app” for the iPhone, iPod touch and iPad. The new app allows users to log into their Facebook account and send pictures, 120-character messages and 10-second videos which will self-destruct after being sent within a set period of time (1, 3, 5 or 10 seconds). Users need to press and hold the message to see it, and once the message gets expired it cannot be retrieved by either party.
Facebook said in a blog post "With the Poke app, you can poke or send a message, photo, or video to Facebook friends to share what you're up to in a lightweight way"
"When time runs out, the message disappears from the app"