Although Facebook has notched up more than a billion users, it seems the company isn't resting on its laurels. It wants more. Already people have predicted the demise of the popular social platform as more and more young people turn to instant messaging services such as WhatsApp and Snapchat to share with friends in a more private setting. So Facebook has a task on its hands: how to entice them back again. Now there is Slingshot, a Snapchat rival that not only allows you to involve your Facebook friends, but also anyone with a compatible mobile phone. The app allows you to send temporary messages to friends, safe in the knowledge that they will disappear once they swipe the shot away. You can't just spectate though; you have to create before you can see a "sling". Facebook wants to create a community, and it wants you to share. So before you can access that all-important message from your friend, you have to send one yourself. It will be interesting to see if Slingshot will prosper where Poke failed.