having all votes public may also be an improvement.
The purpose of implementing voting, as opposed to (for example) soliciting critical/praising comments, is to get more information about people's attitude towards individual comments, by lifting reasons not to signal (and thus lock the community focus better, protecting it from watering down). Commenting would be less frequent because (1) it's more difficult to comment; (2) if you have little to say, or what you'd say has already been said, you don't want to create more noise.
Requiring that votes are made public will discourage some of the voters from signaling their attitude, or otherwise distort the signal for image purposes. I'm not even sure whether voluntary public voting is a good idea, because of the image-driven distortion effect, but since it's presumably no worse than with commenting, it might not be that bad.
[Update: and now there's a fifth discussion thread, which you should probably use in preference to this one. Later update: and a sixth -- in the discussion section, which is where these threads are living for now on. Also: tag for HP threads in the main section, and tag for HP threads in the discussion section.]
The third discussion thread is above 500 comments now, just like the others, so it's time for a new one. Predecessors: one, two, three. For anyone who's been on Mars and doesn't know what this is about: it's Eliezer's remarkable Harry Potter fanfic.
Spoiler warning and helpful suggestion (copied from those in the earlier threads):
Spoiler Warning: this thread contains unrot13'd spoilers for Harry Potter and the Methods of Rationality up to the current chapter and for the original Harry Potter series. Please continue to use rot13 for spoilers to other works of fiction, or if you have insider knowledge of future chapters of Harry Potter and the Methods of Rationality.
A suggestion: mention at the top of your comment which chapter you're commenting on, or what chapter you're up to, so that people can understand the context of your comment even after more chapters have been posted. This can also help people avoid reading spoilers for a new chapter before they realize that there is a new chapter.