What exactly is SMO? According to Wikipedia: "Social Media Optimisation (SMO) is the use of a number of social media outlets and communities to generate publicity to increase the awareness of a product, brand or event. In general, social media optimisation refers to optimising a website and its content in terms of sharing across social media and networking sites."
'Google has stated that their current search engine algorithm factors in 'social signals' to help it determine where a website should rank in a search result page. Social signals are social media-related recommendations, likes, tweets or social sharing that are associated with the brand's website.
Currently, the value Google associates with a particular social media platform and the type of social media activity is not measurable by us. It is safe to assume that Google+, as Google's own social media platform, is the most important in terms of generating social signals. It is also safe to assume that the social signals, which are generated by Facebook and Twitter, are both significant, due to their popularity'.
Via Antonino Militello