Links from Facebook, Twitter and Google+ are nofollow. I imagine any other reputable social site will be the same, given that Google recommends using nofollow on user-submitted links like these.
Nofollow links may still be helpful in bringing traffic to your site, provided you place them where they're relevant and helpful. Nobody will follow a link which looks as if it were placed simply for the benefit of the link-dropper.
The question is
So is there any benefits from those links or there is any other social network providing dofollow backlinks.
If you have anything new to add, please ensure it answers those questions.