Search engine optimization and social media are an odd mix. The basis for SEO is that a certain page is more relevant, better structured, or more often cited (i.e. linked to) by other places on the Internet that are in its community in some way. For example, the shoe store with a great website about shoes that is linked to by a lot of popular online magazines about shoes probably has relatively good SEO for words related to “shoes”; however, websites like Facebook, Twitter, and other major social media presences also have lots of links and text. The pages link to each other, people “Like” each others pages and follow other pages, pictures are viewed, Tweets are shared, etc. There’s so much social activity there, yet it’s unlike most of the Internet.
The gist of the message is that social media is too hard to penetrate for Google, so the data on those pages usually doesn’t contribute to rankings of any sort. This is beyond wondering whether the links from those pages actually contribute “link juice” to a website (they normally don’t). The entire pages on the whole are actually harder and less likely to be crawled by Google’s bots, which means there’s no SEO benefit to the highly popular social media page. That doesn’t mean your social media presence isn’t valuable on its own (i.e. it’s a great place to offer promotions, interact with customers and new people who learn about you, etc.); but the page itself isn’t doing you any direct favors in terms of SEO.
That said, as a DC SEO company, we also believe social media is a great tool for sending high value traffic to your website. For example, a fan of your brand on Facebook or Twitter may click your posts or tweets and find their way to your page. That extra amount of traffic and brand engagement on your website sends positive signals to Google, which help your websites rank.
In short, social media is valuable in its own right, but when it comes to boosting your web SEO, the primary value from those websites will be the visitors sent your way. Otherwise, in general, the page itself and links going out from it to your site, has very, very minimal value.