Not really, well sort of...
What does help is on your webpage you have a link to your Facebook page and ensure your Facebook page is public viewable with a link back to your webpage. Also, having your Facebook name the same as your webpage also helps.
Not sure if the more followers you have of FB the better your ranking. I don't see how that would hurt.
Whether backlinks come from social media or normal websites - a backlink is a backlink - only thing in linkbuilding is to get a variety of links, that has worked for most of my projects. I am also doing some experiments right now, let's see what happens.
If you have a backlink that is hurting your ranking (Google may tell you of it) you best remove it. But if you have no control over that backlink then you can use this Google Webmaster Tool to let Google know not to take that backlink seriously. https://www.google.com/webmasters/tools/disavow-links-main
Just to be clear, a Backlink is a external link on another site pointing to your site. Not a Link on your site pointing elsewhere
I have been seeing various online marketing platforms from which users are having huge amount of traffic and the main sources are facebook, twitter & G+....
Off course back-linking at facebook and other social media's provides you excellent traffic.
Just an example: If you have a business website and the same business has a Facebook profile and both have links to each other, then I see that as a huge Plus.
Sure, People 1st, then SEO. 1st people will see and able to use both links, and SEO (Google) surly has to reward your site some "Google Points"
I need more Likes, to see if Google would reward me more points.