I don't like using my real name on line unless I am 100% sure that I want my statements recorded for all time and available to anyone. Using a pseudonym allows me to be more honest in my opinions and it allows me to join groups without wondering how my membership in that group will be viewed in 20 years. Simply put, if you don't want much input from me or people that think like I do about anonymity, then, go ahead and require a real name.