> It is a shame there isn't a preview button when composing posts.

The delay setting in your profile (mine is set to 2).

New Feature: Delay - https://news.ycombinator.com/item?id=231024

    There's a new field in your profile called delay. It's the time delay in minutes between when you create a comment and when it becomes visible to other people. I added this so that when there are rss feeds for comments, users can, if they want, have some time to edit them before they go out in the feed. Many users edit comments after posting them, so it would be bad if the first draft always got shipped.

    Delay is initially 0. The maximum effective value is 10. It only applies to comments.

Or just more sane markdown handling :/