You can't upload just one email address (they changed the minimum number a long time ago for privacy reasons). There is a minimum number to create a custom audi

You can't upload just one email address (they changed the minimum number a long time ago for privacy reasons). There is a minimum number to create a custom audience of email addresses and then you create a lookalike audience that is 1MM+ people. I don't see how that's a violation of privacy. It's probably the most effective thing Facebook has done for targeting as I use almost exclusively custom audience and lookalike targeting.