One of the questions I get most often is "what does a community manager do"? As a growing field (in as much as any field is growing these days...), there's a fair amount of interest in what community managers do.
Dawn Foster has a great post on this topic over on WebWorkerDaily, though she's specifically addressing online community managers. According to Foster, the key responsibilities fall into facilitation, creating content, evangelism, and evolution:
Evolution. Topics of conversation change, software changes, and people change, which all requires changes to your online community. This is the strategic piece where you get to think about what the community should look like in one year or five years and make changes to the community to make sure that you achieve your goals for the community.
I'd add a couple of things here:
Communication: A big part of any community manager's job is communicating with different parties and trying to get them communicating effectively. She sort of touches on this with facilitation, but I'd put this in a category of its own. This might sound basic, but it's a vital part of the job. A touch of conflict resolution goes here as well.
Everything else: It's been my experience that a community manager handles a lot of things -- like show planning, budgeting, purchasing, and even recruiting sponsors.