You're more likely to have a conversation with a friend of your friend. It's generally much less threatening than talking to a complete stranger. This is how cocktail parties work, people are connected mutually through a friend.
I'd venture to say that most relationships are facilitated through a mutual friend.
When I tell people I go to the bar by myself to see what kind of people I end up talking to, many of my peers are shocked I would do such a thing.
I met my wife at a friend's birthday party, so I'll vouch for that. But there's a difference between <pool of strangers whom I might like to meet> and <pool of strangers I want to life updates from>. I'd venture that for most people most of the time, we just don't care much about the latter[1], which is I think the OP's point.
[1] One time when we may care very much is when we're actively looking for a relationship. I've found that my interest in social networks is highly correlated with those times...
"A friend of a friend" is enough for me to take someone's call if they're asking for a personal or professional favor. Lord knows I've been on the receiving end of enough of those gifts.
The thing I'm noticing lately is most of my LinkedIn invites nowadays are from people that I have never heard of, but have as mutual friends. It's almost as if that space has gotten big enough to let more folks in. Once you have 500+ friends, what's 501+? Though the impact of being so open is sharing less with your friends.
I'd say that is true if you're truly talking about "friends," but since "friends" on most social sites actually means an acquaintance, it's much less interesting.
I'd venture to say that most relationships are facilitated through a mutual friend.
When I tell people I go to the bar by myself to see what kind of people I end up talking to, many of my peers are shocked I would do such a thing.