This isn't just a statistical problem, it's also a classical exploration/exploitation trade-off. You want users to notice and vote on new answers (exploration), but users only want to see the best answers (exploitation). The order you show will influence future votes (and future answers).
In addition, it's a social engineering problem. At least people with a western psychology seem to respond very strongly when a score is attributed to their person (as opposed to a group success like in a wiki). So you better make the score personal and big and visible, and do not occasionally sort by random just to discover the true score.
In addition, it's a social engineering problem. At least people with a western psychology seem to respond very strongly when a score is attributed to their person (as opposed to a group success like in a wiki). So you better make the score personal and big and visible, and do not occasionally sort by random just to discover the true score.