Social networks !!!

Well this is typically the kind of things I can't stand : annotating about a subject I don't believe in like social networks on the internet. To me this is such an artifical way to create a real network : for example when teenages try to have the biggest number of contacts on their blog adding anybody in their list !
But it raises interesting questions like : will Linkedin really help people to find a job ? Why not ? I'm expecting to see that.