Social networking only works when one actually engages in social networking... For example I've seen too many FB fan pages/business pages have zero engagement.. They buy fake likes, twitter followers but all that means is that your post/updates are only ever shown to fake accounts and hence zero engagement.... It does nothing for SEO also....
For organic traffic/growth the best way to promote your social site is to join related groups and get involved with the discussions... and to keep pumping out new engaging content daily...
Personally I don't have the patience and my efforts really focus on using social media to drive traffic to my money site.... In the end making money is what counts... To do that I use ads... Ads which encourage people to signup to a list for a free bonus.... and with that ROI achieved over time through an autoresponder sequence...
I sometimes place ads which only focuses on growing my social page with genuine likes/followers through provision of engaging content... I have found quizzes to be awesome, much like buzzfeed as they can really go viral after the ad campaign has finished through organic sharing....
Another great tactic is to hide content or provide a free report on the condition that you blog post is shared/tweeted... For this approach you dont need a social media page as your visitors are doing all of the work... this approach can really bring in a nice chunk of traffic.....
