Also worth noting is that G+ is in principle one directional when it come to contact so everyone can follow whoever they want to without the other party having to react in any manner.
I must admit I have many two directional contacts from the closed beta period with many of my real life friends when people joined just because and had no idea how different from Facebook this was going to be. Since then I have almost only started following different bloggers and companies and stopped caring about unknown people following me.
Strangely some even bigger companies start following you back even if you produce no content. Maybe they feel that it's courteous or something but absolutely needless unless they want to share something limited to their own circles only which I doubt.