I would think that a healthy community would not have any down/up/like voting system in place at all. A voting model encourages people to judge without comment. If you are posting in a format that uses a voting system, you may be a needy person who wants validation of others, not a discussion on the topic. If any system were to be implemented, I would recommend something like a trending, most shared or most discussed tag to ascertain the posts viability/popularity.
Probably. Everyone likes a gold star. I used to cringe at the students who proudly accepted their perfect attendance award at the end of the school year. Arbitrary awards are the worst kind. And internet voting is nothing if not arbitrary. (I secretly hope this comment gets a billion upvotes and a badge.)