[logfromblammo]

...which does not integrate at all into the employee's existing social tools. Separate accounts. Separate servers. All managed by the company and not the employee. If you have separate accounts for just work and real life, that's manageable. What happens if you also need separate accounts for church/temple/whatever, kids' sports leagues, civic societies, multiple circles of friends from high school, college, previous jobs, and the like?

It explodes beyond the ability of a human to maintain, and user names and passwords start getting reused.

I already have three separate e-mail addresses just at work, and that's a pain to deal with. I have two different personal e-mail accounts, so the recruiter spam doesn't drown out actual friend communication. I don't necessarily want Apple or Google or Microsoft connecting all those for their own nefarious purposes, but nor do I want to be burdened by the weight of my own requirements.