As Facebook ages, it faces an interesting generational problem. As people age, their friendships change, evolve. When they are in school, they might have one huge cluster of friends. Their friend list grows indiscriminately and is rarely trimmed. As they mature and move on in life, that large group of friends is curated, resolving into a smaller list of closer friendships. Facebook excels at building a friend list, but does not do such a great job at supporting the curation process.
Personally, I am rarely interested in unfriending anyone. I mostly want to fine tune who I follow closely, who I share with.
Interesting read. And, I think, an opportunity for a social network that recognizes the unfriending problem and that offers a more sophisticated friend curation solution.