This post is actually a comment I have just left on Euan Semple's blog:
When email hit the corporate workplace I'd had it at home for years but I was unusual. For most people, the use of email at work was quite often their first run-in with it. The thing with introducing social media into the workplace is that... on the upside, many are very familiar with it in a non-work environment, but this is also the downside.
I've run a number of projects recently introducing social platforms into the work environment and one of the major hurdles is convincing people to use it and overcome their out-of-work social media prejuduces (whether they be pro or anti).
If employees are pro-social media outside work, the relative constraints and differing etiquette required within the organisation can be so off-putting they resist making the leap. Those who've taken against social media outside of work for whatever reason are even harder to convince... "social media is just not my thing". In the early '90s did employees say... 'oh... email is just not my thing'? Probably not, because it was new to them and it was being mandated as a business process by their employer.
I'd be quite happy with employers taking a firmer line on mandating the use of social media, but they might need to think about removing the comfort blankets of email and other enterprise platforms in some instances in order to force the issue.