My two cents of down voting
There seems to be a bit of a controversy on the down vote arrow; that it should be used only for reporting content that doesn't apply to one of the tribes that it was posted to, and that people are using it to show their general disagreement with the post instead. These disagreements predate Snapzu and in my experience no amount of pleading or wishy-thinking is going to change the behavior of people at large. People will use the down vote arrow to sound off general disagreement; It's what it's used for.
Instead of a down vote arrow there really needs to be a report button. When reporting a post you should then be required to select from a list of why it's not applicable to the tribe (repost, unrelated, illegal, etc...) and optionally leave an additional comment yourself. Additionally, how the number of reports effect it's standing in tribe feeds should be exclusive to the tribe that's reporting it. If you accidentally post a snap in the wrong tribe, that decision shouldn't effect the posts standing in other tribes that it was submitted to.
Now I'm not saying that the down vote arrow should be completely abolished. There are examples of communities in that other site who hide the down vote through CSS. Likewise there are communities who fully embrace the use of the down vote arrow for what everyone uses it for. Down voting should be an optional feature for moderators of a tribe to select whether or not the down tally will be used in their own tribe's standings. Likewise it would be great if a user could elect to ignore down vote and have them not effect how content is ranked on their home/front page.
Again, these are not my opinions because I think this is they way I think people should behave; these are my opinions on how to represent functions according to the way people do behave.