Someone needs to topple the Facebook monopoly. The only way it stays down is with open standards. We need a social networking protocol rather than a website; a networking standard rather than a walled garden. Eventually Facebook will be too big, and they'll become a monopoly on social networking. We need to get worried about that possibility long before that happens because then it will be too late. Maybe it already is.
I think one of the biggest things we can gain from this idea is the beginning of a reputation economy online. When we are able to tie everything to our own social network, and that network is not controlled by or limited to www.facebook.com, then we can use our network to figure out what our friends trust and do not trust online. All we need is for our friends to start using that new social protocol to indicate that they Like or Dislike certain things, and they will develop an online reputation automatically. And because the recommendations come from your own friends, you're more likely to trust them.
Mokalus of Borg
PS - This doesn't work if you have 4000 "friends", none of whom you truly know.
PPS - Or if you're looking at something really new.