Full voting history, probably, yes. Number of votes (some relation to activity, perhaps) not so much.
Anything that's obviously going to make it easy to reverse engineer anonymous things isn't a good idea, but that doesn't mean you can't still find interesting gems.
I agree. Aggregate stats such as whether a small group does most of the voting, whether the same people seem to vote for the highest ranked items, etc. would be pretty interesting while not giving away too much information.
I am also curious whether a completely open system would work. Has that ever been tried? On a system the size of Reddit or Digg it would be intriguing to see how groups cluster.
Anything that's obviously going to make it easy to reverse engineer anonymous things isn't a good idea, but that doesn't mean you can't still find interesting gems.