Facebook turned its two-factor security 'feature' into spam

Facebook is bleeding users, with external researchers estimating that the social network lost 2.8 million US users under 25 last year. Those losses have prompted Facebook to get more aggressive in its efforts to win users back - and the company has started using security prompts to encourage users to log into their accounts.Sometimes, Facebook will send emails to users warning them that they're having problems logging into their accounts, Bloomberg reported last month. "Just click the button below and we'll log you in. If you weren't trying to log in, let us know," the emails reportedly read. Other times, Facebook will ask for a user's phone number to set up two-factor authentication - then spam the number with notification texts.Raise your hand if you're surprised Facebook would do this.