I'll add to this: for truly egregious or prolific abusers (spam, misbehaviour, etc.), both flag and then email the mods at hn@ycombinator.com

(You don't need to do this for garden-variety stuff, but if you see something going above and beyond, it can help.)

I've done this many, many, many times, on all manner of issues. Dang almost always responds within an hour or so, rarely more than a day. Quite often the issue's already been dealt with, either automatically (HN's more complex than it appears), or by mod intervention. Occasionally (and increasingly since I've tightened my own criteria for reporting) I seem to be reporting unrecognised abuse. That's not because the abuse is more common, but because I'm reporting issues less frequently and after additional checks, e.g., looking for previous mod admonisments.

You can check for this past history using the "replies" endpoint, which can show where a particular profile's had direct responses from dang. For myself, e.g.:

  https://news.ycombinator.com/replies?id=dredmorbius&by=dang

Keep reports brief and specific. Link directly to relevant content or profile(s) within the body. If you're reporting on content, include the content ID in the email subject as this apparently makes processing reports much easier.

E.g., the content ID for dang's comment above, URL:

  https://news.ycombinator.com/item?id=42570159

Is "42570159" (the digits at the end of the URL).

You'll find similar contentIDs on all submissions and comments.