(Reposted from the awesome Quora)
CRM is (should be) about understanding where the customer is on their journey through life, with some appreciation of the trajectory they are on (in terms of behaviour, demography and attitudes, possibly defined momentarily by where they came from and how they are currently influenced); in turn this allows marketers to decide what to say next to influence their behaviours and attitudes to develop additional value.
With that approach, social media is or could be (ideally you should test several channels to see which one delivers the behaviour change most effectively) one possible channel to deliver that 'next message' in the intertwined customer journey and brand journey.
Looking at it like that it becomes straightforward to set KPIs and measure results. This in turn makes briefing experts and suppliers very easy – they no longer have to be particularly creative, nor do they have to compete for budgets against other channels, because their role is tightly defined and they have to recognise they are just one of many touchpoint executors with (sets of) defined goals.
The other way of doing it is to try and box some stuff into 'e-marketing'. If you're not yet at the stage of evolution as a business or as a marketer that you are able to think in strategic terms then social becomes tactical and is all about the creativity of the idea in creating competitive advantage for the supplier in increasing its share of the budget of the various other e-marketing activities.
I really hope the first approach is the one your firm is aiming for ;)