It’s headlines posted to HN that follow HN rules that the HN user thought would be of interest to the HN community.
HN sees a lot of non-techy submissions, and only some of them get downvoted out (most are simply ignored).
So while this results in a ratio of technical to non-technical "headlines" that's not representative of the Internet as a whole, it's still pretty much not very HackerNews-specific. If it included a reasonable minimum upvotes requirement (100?), then it might be.