UPDATE added at the end
With the introduction of the ‘subscribe’ feature, you don’t need to be friends in Facebook to connect with somebody.
Facebook is slowly adding Subscribe button, on friends’ and others’ profiles so that Facebook users can choose what they want to see from people in News Feed and they can also hear from non-friends, if interested.
To let others see the message in their subscription list, the post should be ‘public’
When I logged in my Facebook account I got the following message:
When I clicked "Allow Subscribers," I was asked to choose what to let subscribers access: