individual vote selling is gonna be way harder to police, through a market or otherwise. The tribe leaders / curators have been pretty active in keeping the tag clean and if it becomes obvious that vote buying is sending posts to trending, I imagine they wouldn't have a problem muting the larger accounts that sell individual votes (and they would definitely flag strip the curation rewards from posts that reached trending creativecoin by vote buying). I don't think there will ever be a way to 100% prevent vote selling, but just stopping the largest / most easily accessible bid bots/vote sellers should make a huge difference in terms of allowing manual curators to not get flooded out of the total rshares awarded in creative coin.