More types of flagging? 
gruseom: I hadn't noticed the site getting nastier (and since everyone seems to agree that it has, I'm now regretting a recent nasty comment!)Regarding flags on comments (not stories), I suspect it might have more of an impact to add just one new type rather than several at once. That would send a clear message about what we're all being asked to focus on. Along those lines, I'd say "uncivil" is more important than "frivolous". In my observation, over the last few months, HN users have gotten pretty good at using downvotes to regulate the merely frivolous.If someone's comment has been flagged as uncivil it might be helpful to inform them of this with a call to action such as "Please be more polite" and a link to a fuller explanation of what they are being asked to do. I'm quite sure that many (though not all) people just don't realize how their comment might come across.Perhaps comments flagged as uncivil could remain editable for a longer period. It's true that this would distort the history of conversations a bit, but maybe in a good way. If I find out that I made a comment that people found rude, I'd like the option (after my two editable hours have expired) of editing my comment for civility and having it marked as such. After all, if one is found "guilty" by a jury of one's peers, it's good to have a way to make amends in addition to the negative feedback. Besides, if people started noticing comments that had been "edited for civility", social proof might nudge their own behavior in that direction.