bill - 1:41 am on Dec 22, 2012 (gmt 0)
Introducing Poke for Mobile [newsroom.fb.com]
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. You can poke an individual friend or several at once. Each message expires after a specific time you've set, either 1, 3, 5 or 10 seconds. When time runs out, the message disappears from the app.