Facebook Link Building

Hey,
Does any1 knw is there how google looks at facebook links as quality links? I know that google + and twitter has a trust rank, does FB has one too?
what about shares? ( is it the quality or the quantity?)
If I get lot's of posts shares would it be better :
1. shares from profiles ?
profiles with lot's of friends and active or it doesn't meter?
2.shares from fan pages?
fan page with lot's of like and active or it doesn't meter?
*** is it all about the mentions?****
as many shares and like i'll get?

Google counts the Facebook total for links (Shares+Comments+Likes) . It is better if if they are from diff accounts and authority accounts.