I am part of some online „communities“ but then again, I'm not—somehow. It's funny as I regularly contribute to some of them, namely Wikimedia Commons, Wikipedia, Rosetta Code and Stack Overflow (and its relatives). Now currently there are elections for new moderators on Stack Overflow and I (as most users) was asked to vote:
But I honestly can't vote there.
The problem is that Stack Overflow is largely content-based. Whatever there may be in community is mostly driven by content and not by the users. Which means that I could judge the candidates by the content they contribute which is easy enough but doesn't tell me anything about their qualifications as a moderator. Equally unsuitable are the moderator nominations, mostly done by the candidates themselves and their user profiles; they simply aren't an accurate picture of how well they would do their job.
Stack Overflow goes great lengths in pushing the actual users into the background, emphasizing the questions and answers. There is a little incentive to continue contributing, namely reputation and badges; I'm playing that game too. But overall it doesn't really matter for Stack Overflow to keep specific persons there—as long as the contributions are still there and of high quality, no one can complain. But ultimately you don't really know about those people. You know about their technical knowledge and how they write or how willing they are to provide outstanding answers. But about how well they would perform as moderators? Nothing. While sometimes discussions arise in the comments on a question or answer they are mostly very short-lived, just as the questions/answers themselves (most questions, even those with stellar answers vanish after at most a few hours and no-one reads them anymore). What's more: comments are de-emphasized on purpose: smaller font size, gray text, hidden by default (except for the top-rated comments). As a discussion medium, where I could actually see how people approach problems, how they deal with it and ultimately solve it, this is a complete fail; again, on purpose.
Stack Overflow isn't alone in this regard; I just picked it out since it's the one example I'm most familiar with at the moment. The problem is similar for me at Wikipedia where the means of communication are comparably arcane and inefficient. Mostly you're communicating with a large blob of vaguely human form which could be anyone. And most of the time you don't talk to the same persons regularly. To me it is surprising that (at least for the German Wikipedia) many people participating in discussions, polls, &c. seem to know each other and are actually talking there. Maybe I'm the ugly kid who stands besides all this or maybe I just didn't see a suitable way of getting to know the people behind the content.
Ultimately, there are probably persons who could judge how well someone is suited as a moderator: Those that have access to logs that detail what moderator-like activities a person has done. For Stack Overflow this would include things like close-votes on questions, flagging questions and answers for moderator attention—that's the technical side. Then there's the human side which necessarily includes discussions (such as what makes a question programming-related). But discussions are, as noted, very much de-emphasized in contrast to questions and answers (which tell me only about technical problems someone faced and was able to solve).
For the normal user there is simply no easy way of looking at the things that would matter in this regard and help in a decision. As for the candidates: I've never had anything to do with the vast majority of them, except for two.
Well, back to my original point, I find it a little weird that such sites ask their members about positions that need certain qualifications, who—by definition and purpose of the site—don't know each other well enough to make an informed decision on that. I see it as a kind of pseudo-democracy where the site owners/administrators give the „community“ something to decide. But in the end I doubt the final decision will be made with regard to the actual qualifications of the elected person. The votes itself are probably rather random for most people participating in the election or maybe guided by prior advertising on behalf of the candidates. I don't remember the original nominations of the candidates anymore but what I read of them didn't strike me as convincing. Heck, not knowing those people I couldn't even decide whether their application/nomination was meant seriously or is just full of senseless talk.
I think such sites should either make actual communication (read: social behavior of people) part of their purpose (not that I see this necessarily as a good thing—I'm part of no social network for a reason) or stop trying to pretend they have a community. In fact, they haven't, in my opinion; they have content, they have people that contribute it; but they have no community.