You'd be forgiven for not knowing that Facebook has an external email system built in to the site's familiar messaging system. After all, few of us have need for yet another email address. And given the way Facebook algorithms decide to hide messages that the site doesn't believe is important, we're absolutely terrified of losing important messages.

The fact that you're not using that Facebook email address appears to have led to Facebook trying to figure out new ways to push you to the system...