Great post yesterday by Chris Brogan: What I want a Social Media Expert to Know. Great comments too.
To expand on his post: What a social media expert should also know is that the answers -- if you re-frame Brogan's list as a set of questions -- can be different in different situations, with different companies and industries.
The social media expert might not be able to answer the questions correctly -- and with a high degree of certainty -- in all those situations but at least s/he should know (a) that there will be differences, (b) where to look to find the right answers for that situation, and (c) if there are no right answers, make a pretty educated guess as to what they will be.
I know this to be true, by the way, because I've worked both on external-facing web portals and internal-facing intranet portals and some of the answers to Brogan's questions are vastly different in those two cases.
Still, like he says, social media experts should have answers to all those questions. In fact, I'd expect a good social media job interview to cover most, if not all, of these questions as well.