Why not have an option to let people pick their 'Display Name', different from their user name? The display name can be anything; and should be @taggable. Why? We've seen that the engagement of users with the site has gone up 10x ever since we started asking people to use their real names on the site. But using real name has disadvantages; there can't be two people with the same name (username). We'd like people to use their real names on the site and they should be @taggable.