Social Media & Public Relations: Which is Which?

PR has always been a social channel.  The holy grail of “earned media,” which means the mention of your brand in a traditional media source like a newspaper or magazine, was considered to be so meaningful partially because the “impression” metric that media outlets like the New York Times gives you wasn’t just about the number of eyeballs: those eyeballs belong to a person with a mouth, and viral word of mouth is what makes any earned media exponentially powerful.
By the same token, social media is the most public relationship of all: rather than a middleman (i.e. a reporter) espousing the value of your brand to the public, your social media manager is a real-time brand bullhorn talking directly to the public.
PR pros have been talking about the issues and disruption that social media raises for PR since its inception; the move from the traditional PR monologue message to the social media dialogue marketing model was the first sticking point for traditional PR folks, who were accustomed to controlling their message.  Then, we started seeing articles about finding online influencers, brand advocates and the new citizen journalists, which blurred the lines even more.
It’s no surprise, then, that – as social media sites and marketing as a discipline matures, and we debate whether or not the social media manager is dead - we’re seeing PR using social media tactics and channels, and seeing social media marketing managers getting a better handle on staying on-message.  Both disciplines are, at their core, content marketing disciplines: we’re putting content out there into the world to be consumed, and whether it’s on earned or owned media, the power of content marketing is engendering a share that gives your brand more positive impressions among your target social community.
What will the next 5 years hold for Social Media and Public Relations?  Well, my best guess is that we’ll see either dotted lines or a collapse under larger headings like “Brand” or “Content Marketing,” as the marketplace matures and people understand that a channel is a channel, and it’s the larger marketing and business goals that should be the focus.