Hey Everyone I have discovered how to get do follow back links from face book, maybe you guys already know it. Here what I did, I posted my blog link in one of the groups on face book and google counted as back link you can see it here http://hi-in.facebook.com/group.php?v=wall&gid=10345376411 , If you post your link in good group and the wall of that group must be active, you'll get quality do follow back link
( although it was not do follow link but I am amazed it is still counted as back link in google when I search number of back links in google for my blog)