1. Structural issue, something to do with HN running off flat files on one machine.

2. shrug

3. No comment.

4. PG has said that he wants to add undo, but doesn't think it's a big enough deal to patch it.

5. All upvoted stories are saved automatically.

6. That would be nice.

7. Supposedly it skews the ranking algorithm in your favor. At 500 you get the downvote.