For the most part, I think community is still largely about building relationships with users, but I’m seeing more and more that companies are putting emphasis on marketing related activities.
Social media is about engagement first and foremost. Sales are complimentary.
Social media is no longer just an aspect of community, it has grown into a fulltime focused position that requires vertical/platform specific strategies and content generation experience. Each platform has its own weird ins and outs, with different communities requiring a different approach and unique platform uses.
No two platforms are the same. Vine requires its own unique content strategy from Instagram video. Twitter speak is vastly different than Facebook, although Facebook seems to adopting the Twitter language.
Everyone can do social media. But they don’t always put “the right content in the right places.”