Content marketing, social media, video, and public relations affect a web presence and organic search rankings. These tactics can have a significant positive impact on SEO including: rank, backlinking, social signal generation and fresh content.
"Social media and SEO are very much separate line items in a marketing budget, but content socialized at the page level through Google+, Facebook, Twitter, Pinterest and YouTube generates social signals which can positively impact SEO and an organic search ranking.
The most direct link between SEO and social media is Google+ and Search plus Your World. If you haven't yet started to build out your personal and business Circles, please do. A piece of content shared through your Circles has an opportunity to be found by your followers through Search plus Your World – before your competitors’ content is found".
Via Antonino Militello