What to Submit On-Topic: Anything that good hackers would find interesting. That includes more than hacking and startups. If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity.

Off-Topic: Most stories about politics, or crime, or sports, unless they're evidence of some interesting new phenomenon. Videos of pratfalls or disasters, or cute animal pictures. If they'd cover it on TV news, it's probably off-topic.

It's one of the old-school breed of "labor of love" informative websites that HN often waxes poetic about. And it's very interesting!

Try setting "desktop view" in your browser if possible on mobile devices, as the mobile website is spectacularly uninformative.

Desktop isn't much better.

Typically because it was upvoted enough.