They're not, they're just getting flooded out by other posts. There's been at least 20 in the last day, but only a tiny percentage (low single digits) ever make it to the front page.
Possibly due to Summertime, I am constantly checking <a href="http://showhnapp.herokuapp.com/" rel="nofollow">http://showhnapp.herokuapp.com/</a> it shows every post that contains the words "Show HN". That's how I found this post!
I look forward to the MetaShow HN, a webpage that collects links to each Show HN posted, which includes a post about itself.<p>Interface with github/bitbucket to get the languages and licence info and auto tag.
You can use hn webapp <a href="http://hn.premii.com" rel="nofollow">http://hn.premii.com</a>. There is an option to filter show and ask hn stories.