I don't believe down-voting discourages discussion .. I'd argue it often provokes it.
Not that I have been able to figure out the magic that gets you the ability to downvote, but I don't really feel the need.
But indeed it sinks discussions, since the points are one the ways (not the only one) to sort comments.
Not that I'm really worried about it one way or another, though.
Not that I have been able to figure out the magic that gets you the ability to downvote, but I don't really feel the need.