Facebook will never embrace 'shades of grey' because it has this ethos of exuberance that says everyone you meet is a friend and everything is worth liking, if only to differing degrees. Don't underestimate this, it creates an environment that feels safe, especially to advertisers. this benefits Facebook in their quest to get people to share their lives as publicly as possible, which they may not do if they feel even subconsciously that there is a risk of negative response.
Article is interesting, but commentary is more so. It's personally very alien to this nugget *why* people "like" things on Facebook without incentive.
On the other hand, the nugget has 4 'friends' (or was that 5), and likes only things that work requires her to like. In fact, the only thing the nugget has "liked" of her own free will is Forsaken World - precisely because they incentivise it.
The marketer in me loves the comments section though, it's a great look into the brains of the masses I am supposedly brainwashing!