This is actually a great milestone. It is hard to build a sustainable billion dollar business on "being cool" because any minute society might decide you're no

This is actually a great milestone. It is hard to build a sustainable billion dollar business on "being cool" because any minute society might decide you're no longer cool and move on to the next shiny object. Just ask myspace. Facebook isn't a billion dollar business because it is the new shiny object on the block. it is used because it delivers good old value of helping you stay in touch with your friends.