How is the potential reach of a mention calculated?

Potential reach shows the number of people that have potentially read an article posted on a news portal. It is calculated based on Neticle’s own formula.

Why is there a potential reach displayed for some Facebook mentions and not for others?

Reach for Facebook posts is calculated by NMI’s own calculation method that uses follower counts and all types of interaction data that is available about the post creator and the post itself. In case interaction data is not available for a post, no reach number can be calculated.