Just when you got it all figured out, Google comes along with Panda, the latest algorithm for their search engine, and changes the game. A lot of what used to work now doesn’t, and it’s hurting content farms, like How.com and About.com. But social media news giant Mashable seems to have a handle on it. By strategically placing social media links above advertising banners, they’ve managed to remain at the top.
Alternatively, Sports Illustrated puts their social links on the bottom of their site and gives priority to print and email buttons over social media icons, thus making people have to “work” harder to share their content.
The goal for Google is to bring more relevant content to the top of search results, give you more of what you’re really looking for, and weed out the automated, mechanical info. By bringing the best content to the top, which Google believes to be what is shared most frequently, it becomes obvious, and necessary, that sites make it as easy as possible for people to share their content.
http://emediavitals.com/content/seo-vs-smo-why-google-may-favor-social-media-optimization