There's no need for real names, what is needed is that you can't create multiple accounts. This can be done without linking identities by using two unrelated parties. Party A is the platform and B is the authenticator, when creating an account on A you are sent to B to authenticate your identity and get a token to finish your account creation on A. As long as A and B are separate, A never knows the identity of the user and B doesn't know what the user represents himself on A.