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.
no one can downvote submissions, regardless of karma. The reason this is on the front page is that at time of writing, 32 people found it interesting enough to vote up. If you don't like the article, don't read it. Your post is not useful to anyone.
http://ycombinator.com/newsguidelines.html