Because the presence of public circles (channels, topics, columns) need in no way dilute the current functionality of (private) circles. G+ is where the audien

Because the presence of public circles (channels, topics, columns) need in no way dilute the current functionality of (private) circles. G+ is where the audience is at, so that's where Notch would like to broadcast. Obviously a large number of fans are already following him for the purpose of getting this specific information, not noise on other subjects. If we don't enable that category of user, they're going to depart for greener pastures completely (rather than alienate their fans with a poor experience).