If Facebook wants to know if your account is active, they can determine this whenever you use your account, without asking you to do some silly things like sending a message to your friends.
The Facebook Hoax and Scam
Hello, we are the Facebook company... You will have to send this message to 20 people to stay active. If you dont do this your acount will be disconected. If you think this is fake please call customer support on this number: 316-691-9111
Thank you for choosing Facebook as your social media app.
So, if you have gotten this message, please do not follow the instructions in it. The telephone number in the message is not associated with Facebook, so please do not call the number. We called the number and no one answered. But got a call back from a man attempting to acquire our credit card information, which he claimed is for a "necessary donation."