here are three strategic points worth thinking about from a social and SEO perspective.

Social shares ? Tweets, Likes, Google +1?s, etc. ? carry weight in Google?s ranking algorithm, but as yet it?s hard to establish more than a ballpark impact.
In contrast, social media content and shares have a clear and significant impact on display visibility. Original Google+ and/or blog content is indexed and displayed in regular, personalized, time-sensitive and social subsections of a SERP. Content endorsed with shares by your social connections is visible. (Original Twitter content has been devalued lately, but I think in the long term it is likely to gain prominence.)
User behavior and preferences are critical element in devising SEO strategy. The importance of display visibility depends largely on whether a user is logged into Google, and the extent to which a user has an active social media network. If your target market is not logged in and/or has few active relationships, traditional search results are all that will matter to them.