I personally can't see neither the "limited notion of social relationships"
So you only have one binary relationship with everyone(friend\not friend)?
In the context of friends of friends I can see several different categories: current friends(I might be interested in who their current friends are. I might run into their current friends while hanging out with them. I am probably not interested in their old friends who live 500 miles away.), old friends(I will probably never interact with their current friends because they live 500+ miles away. I maybe interested in their old friends because it might help me reconnect with a mutual old friend.), family(I don't want to see their current or old friends since I don't have anything in common with most of my family.)
> So you only have one binary relationship with everyone(friend\not friend)?
Basically yes, but let's place the binarization threshold on whether or not I recognize someone and care enough to have a conversation with that person in the future.
Neither Facebook, nor real life support an explicit "scale" of friendship. You don't define someone as 90% - BFF or 63% - just friend, etc. Relationships are defined by shared experiences and mutual feelings, and those are supported by the Facebook platform in the same way as they are supported by the direct face-to-face communication platform.
In other words, Facebook stores connections explicitly (calling them "friends" might be what confuses people), but is otherwise as much of a sandbox as the real life. You can do whatever you want, talk with whomever about whatever you care - that is what creates friendship.
So you only have one binary relationship with everyone(friend\not friend)?
In the context of friends of friends I can see several different categories: current friends(I might be interested in who their current friends are. I might run into their current friends while hanging out with them. I am probably not interested in their old friends who live 500 miles away.), old friends(I will probably never interact with their current friends because they live 500+ miles away. I maybe interested in their old friends because it might help me reconnect with a mutual old friend.), family(I don't want to see their current or old friends since I don't have anything in common with most of my family.)