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.
Doesn't say anything so! Moreover, confirms it's off-topic and it's a TV news too.
If the US were putting journalists in Jail, it would be equally relevant. Geo politics, yes, as in whatever is going on between Egypt & Qatar. But I'm interested whenever folks like journalists, artists etc are targeted. Snowden was all over HN & you might argues that's political too, but relevant to this community nevertheless.