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I think this is more of a question about the nature of SO users. I see a lot of questions with 5 or 6 answers, but 0 up-votes. I realize that sometimes that may be because down-votes and up-votes cancel each other out, but in a lot of cases people will just answer, and not up-vote.
Isn't answer a question implicitly indicating that you feel it is worthy of the time it takes you to answer? If I answer a question, I will (almost) always up-vote the question.
I also realize that a lot of times people will answer a question that they feel needs to be improved upon (needs to be clarified, formatted better, etc). In those cases I don't up-vote, but I find those cases to be in the minority of the questions I answer.