(CNN) - Back when Facebook only had millions of users instead of a billion, before Timeline and the outrage over privacy issues, people "poked" each other on the social network. The poke, which is still around but rarely used, is a minimal communication -- the digital equivalent of a head nod or wink.
Facebook expanded the poke into a stand-alone app, called Facebook Poke, which allows users to send fleeting messages, pokes, photos and 10-second videos to Facebook friends.
The messages expire after a set period of time, from 1 to 10 seconds, and cannot be retrieved by either party again. This makes the app perfect for sending salacious images without leaving a trail.
But, it’s not doing so well.
Facebook's “Poke” app hit number one in apple's app store when it was first released -- but it is now not even in the top 50.
The Facebook Poke shamelessly imitates Snapchat, a photo and video-sharing service that has surged in popularity over the past year. It's no mystery why Facebook is jumping on the temporary message bandwagon. Snapchat says it has millions of users who send around 50 million messages a day. It is also popular with the highly valuable younger age group, though it doesn't currently have ads or any other way of making money off of its service. The Facebook Poke app is also ad-free for the time being.
The allure of self-destructing messages is that they are unlikely to be seen by anyone other than the recipient.