Could anyone tell me (Ok, I’d prefer write) what this is all about.
Sure, if you sign up here, then you are agreeing to only use one screen name per time you post. So if you come online for one posting session, you can only use one screenname the whole time. If you want to start using another one as a sock puppet, you need to log off and walk away from your computer and then come back.
Compliance is verified by other posters deciding that you are using sock puppets.