I think people keep confusing "like" with "follow".

Just because I "like" Sierra Nevada beer doesn't mean I want updates from them, maybe I just wanted to like it because AirTime will then use those likes to link me up with someone else who likes Sierra Nevada beer. On the other hand if I follow Sierra Nevada on Twitter its because I want to see their every 140 character thought that they feel like sharing.

That being said I think he makes a good point about differentiating between brands, artists, non-profits and individuals. Perhaps they should just expand on "Subscribe", their version of "follow", so users have the choice.