Not fears and concerns so much as disappointment with Facebook's impoverished version of friendship...

To address your substantial point: yes, of course social structure is hierarchical. You have close friends, you have more distant friends, you have acquaintances - that's a hierarchy of closeness and affection. Overlay that with the variety of social domains you inhabit (close friends in private life, close friends at work, close friends in clubs and societies you belong to; more distant friends in private life / at work / etc.; private / work / other acquaintances), and you have a heterarchy: a social network with multiple peaks and troughs. Having just seen Mark Pesce speak on precisely this point, I'm perfectly happy to agree with him: that's how, as social beings, we've interacted for millennia.

Flattening that into calling everyone a 'friend' is very clearly an oversimplification which has little to do with reality, and is likely driven by other motives. Your comparison with 'flattening' commodities into their equivalent in money gives you away there: when you flatten goods by representing them as a money value, it's no longer about the specific goods at all, but about how affluent you are (how many bananas, cigarettes, whatever you can buy); when you flatten your social network into some absurd Facebook number supposedly indicating how many 'friends' you have, it's no longer about the quality of social interaction, but about the mere, mindless competition to have more 'friends' than the next guy.

As for your second point - dunno. Don't get what you're trying to say.