>>pg+(OP)
I know this is an early version and things are still a bit rough, but just for the record:
1) The number beside my user name (top of the page) is a bit confusing. At first I thought maybe it meant I had some sort of message waiting to be read, or perhaps that I'd made one comment, which didn't make sense because I'd just created the account. Perhaps a label before the number would clear things up: (karma: 1).
2) I didn't realize at first that the arrows were used for voting. The main page (http://news.ycombinator.com/) had only "up" arrows. I figured they were used to collapse/expand additional content, so I ended up inadvertently trying to vote for several arbitrary items (I hadn't created an account yet, so the votes didn't count - I don't think). Once I saw the "up" and "down" arrows together I got their purpose. Perhaps, instead of removing one (or both) of the arrows you could simply display a ghosted one? Or perhaps replace the arrows with thumb up/down icons?
3) "7 points by pg 1 hour ago | 7 comments" reads like you (pg) added 7 points an hour ago. Is this meant instead: "7 points | by pg | 1 hour ago | 7 comments"?
New feature: Why not combine the scoring with Flickr like tags. Instead of just being limited to increasing/decreasing an items karma, give me the