Whewww, that certainly got a lot of discussion. Rather than address each post individually, I'll attempt to summarize all my thoughts here on one node.

Null vote option -- Not much opposition to this one, most people seem to like it (or at least not dislike it.) It's an implementation issue more than anything.

Public upvote/downvote percentage -- I thought there would be more concern about this one, since it violates one of the core issues of voting, namely that it is private and confidential. I'm a bit squemish on this one, but I didn't here too many complaints, probably due to its aggregate nature.

Possible loss of XP for downvotes -- This seemed to be much more controversial than the other two. Unfortunately, I think it might also be the most effective at curtailing the personality votebots that seem to be the most troublesome.

Put yourself in the position of a votebot writer. As the system stands now abusing the system is trivial. Grab the links off of someones home node, then downvote any of them that you haven't already voted on. As an added bonus, you get XP for doing it, which means that tomorrow (or next week) you'll be able to cast more downvotes. The problem gets worse as time goes on.

Now consider a system, where on average even a smart votebot would lose XP. Over time, it will start to lose votes (if you just look a the votebot part of the persona) and the problem begins to correct itself.

The trick is to design such a system. (yes this does smack of an arms race, but vroom gets to set the rules, so it should be possible to win this one) Assuming that the voting system is mostly functional (which I think we can all agree to) a nodes rep has some correlation to its overall relevance to this site. Therefore, a downvote on a highly ranked node is likely to be a downvote on a highly relavent node.

I would even argue that time plays a factor as well. Over a span of time a nodes rep gains a higher and higher correspondence with its relavence. Therefore, downvoting older nodes (say like 1 week ago) also seems suspect.

The possiblity of losing XP would be:
1.) Proportional to the current nodes rep
2.) Proportional to the current nodes age (in days, not minutes)
3.) Inversely proportional to the voters upvote/downvote percentage

If these rules were in place, gaining XP with a downvoting votebot would be very difficult. You'd have to grab recent posts that weren't highly ranked, and have to keep your upvote percentage above some threshold. This severely limits the possibilities of abuse. It would also allow targets to take a day off without getting attacked, because there wouldn't be any "safe" nodes to downvote.

-Blake