Having said that, I am gearing up to do a Show HN in the next month or two. I read hackernews and the comments pretty regularly (I especially pay attention to the comments for the Ask HNs and Show HNs).
One thing that I have noticed is that there are a number of sins you do not want to make with your app when doing a Show HN or you will likely have the discussion/comments centered on those things alone.
So I ask of you, what are your biggest pet peeves or cardinal sins of apps posted to Show HN?
Sins I've seen or mentioned in the comments below:
* No demo and/or no screenshots
* Forcing people to sign-up for a trial or login for a trial
* Unclear message about what the app actually is
* Unclear message about why I would use said app
* Untested across the latest browsers (e.g. works on newest chrome but not on Firefox)
* Bad typography choices and/or hard to read text
* over-reliance on boostrap for style (I am currently guilty of this one)
* the web app breaks on mobile device
* spelling/grammar mistakes
* site goes down from number of hits
* no link to the actual website
Yours?
Edit: adding some of the good sins from the comments