This is a meta thought, generally these are submitted as a link and then context is provided in a comment. Not sure that that's a better way of doing it though. Might generate more visits.
Oh, whoops! I had figured Show HN was more about the discussion but that's a great suggestion, since people can come comment on it anyways. Thanks for the tip!
For the discussion part, you can just write a comment in the thread itself. That what the show bit is the thing you want to show and the things you want to say go in the thread.
