Yes, and AFAIK, sharing-on-your-feed is exactly what Tumblr's system is, and that hasn't exactly turned out to be a bastion of... anything, really.

If Hubski seems good so far, it seems more likely because of the community than any underlying system. I like the community, but things like the prevention of insular groups(and the resulting brigading) is legitimately hard... How is hubski's system equipped to handle these problems?

(Edit: just to be clear, I don't intend this to be snarky, I'm legitimately curious about this problem. Reading through the primer now.)

But isn't this pretty much how Tumblr works now (vote=repost on your tumblr)? There doesn't seem anything implicit in this scheme that will directly lead to thoughtful conversations... It seems more like a function of the community rather than the vote system (/r/AskHistorians is a good example)