Back in the 90s, and probably well before then for all I know, the phrase "sales is everyone's job" was thrown around with all the loose abandon of Mario Balotelli's potty mouth. Clearly, not much has changed. Substitute "sales" for "social media" and you have the modern day equivalent. It's become fashionable to say it, but impractical to do it.
Let's run with this theme for a moment. The vast majority of the population will either have sold something on eBay themselves or know somebody else who has. That doesn't make them a salesman. Similarly, everyone has used social media at one time or another, or at least knows someone on Facebook. That doesn't make them a social media expert - no matter how many virtual friends or 'likes' they have.
While this is clearly over-simplification of the issue, there is a slim likelihood of any firm - large or small - defining social media as a pre-requisite skill of every employee. Try pitching that idea to a financial director, or even a HR for that matter, and you'll probably be laughed out of the door.
More likely is the scenario whereby all, or most, staff are engaged with internal social media platforms, such as Yammer, which enable people to get connected with the brand and each other. This is because the internal view is very much different than the external one, which is why disciplines like PR are often outsourced rather than insourced. Is it right to say that PR is everyone's job? A little, perhaps, but not a lot.
Marketing, sales and IT-led business operations will naturally drive social media externally, because it is their job to do so. Just like Henry Ford's 'division of labour' assembly line, it is time and cost efficient to do it this way. And that's also why - using the agency analogy - PR departments tend to generate content and manage social platforms for clients (in lieu of specialists, of course). Creative, digital and design departments collaborate on such initiatives, usually at the early stages, but the ongoing donkey work usually resides with those who have the core skills to sustain the community spaces - namely copywriters or, more broadly, good storytellers.
From experience of training in-house teams in social media, the results can be gratifying and depressing in equal measure (depending on the company's culture). But in all positive cases, success has been achieved with a small, carefully selected and motivated team. Volunteering is important too, because employees need to want to be involved, rather than being cajoled, forced or threatened by their 'superiors'.
Whose job is social media? Seek and ye shall find.
If you ask everyone if they want nine to five access to Facebook, almost all will jump up and down excitedly like demented teenagers. But if you ask them "who fancies writing a blog and 10 tweets a day for the rest of their working lives?", watch as people start hiding from, or pointing at, the lunatic with the big idea.
Social media can be a major undertaking, which is best directed by those that know it well (marketers) and should be informed by those who know the audience well (customer facing staff). But, remember, being involved and managing social media are two very different things.
Communicate to many, but do it with a few.