It just means that tu haven't invited anyone to fanpop por sending an invitation/email yet. If tu go on your profile, below the box with editar Profile, Change contraseña etc, and above your favorites, there's a yellow box with the text "invite your friends". Just click on that box, and when you've choosen if tu want to invite friends via correo electrónico o social networks like facebook o myspace, and clicked send, a message will be sent to that person with an invitation to registrarse fanpop. If the person accepts the invitation and joins, the little icono will change, and instead of the number O there will be 1 on it. Read more:
link
