Why the tech requirement? It's HackerNews not TechNews. There are plenty of good posts I've found useful which fit the hacker label but not the tech one.
If they are well-written but don't involve technology, they don't activate the flag criteria. I may even upvote them if there are cool enough (many New Yorker essays, for example).
If they are poorly-written but do involve technology, they don't activate the flag criteria. I simply won't upvote them.
If they are both, they are taking up link space.
(I'm also personally opposed to the "Let's use hack to describe everything!". That said, I do appreciate good writing--for example, the piece on Frank Lucas that showed up a while ago.)
"Bird Bath: The Conservation of a William Morris Textile"
I didn't click flag because I have a certain fondness for dead media preservation, someones going to be writing something very much like this in 50 years for preserving 5.25 floppy media, or flash drives, or a museum preserving its vintage iphone 5, which gives you something to think about. And, after all, its jacquard woven which means a lot to CS/IT/tech people who know what that means (which is probably not many). But its really darn close to the line and I would not feel its excessively outta line for someone else to click flag, if they want to.
Whenever this matter surfaces, I recommend the HN Slapdown user script [1] which indicates stories that have been moved below the position they would have based on points only. In other words, it draws attention to stories that have been flagged or otherwise adversely affected.
In my opinion, the homepage either weights non-upvote inputs too heavily or receives too many non-upvote interactions from users.
I can't be certain whether flagging or other measures such as the "flamewar detector" are more or less responsible for the volatility of the home page ranking. My only anecdotal evidence is that when I have (very rarely) flagged stories, I've witnessed an immediate and severe rank adjustment, often immediately sending the submission into second-page purgatory. This has given me great respect for the severity of flagging.
My heuristics:
1. Most of all, I try to keep my interactions positive. If I don't agree, I act as if I don't care, by which I mean I do nothing. I see little value in downvoting something I disagree with. It won't change the person's mind—only a comment in reply has a chance of that.
2. I will downvote comments that I believe are objectively wrong and potentially misleading to other readers or are clearly intended to be offensive or mean-spirited. Still, I feel I am very sparse with downvotes. I downvote approximately one out of every 1,000 comments I read.
3. I've only flagged stories that are unrelated to technology, but even then only in extreme cases. I don't bother flagging stories about popular fiction, movie reviews, or other elements of geek culture because I don't think those stories are an epidemic at HN. Like you, I feel it's important to leave a comment when flagging a submission. I have flagged two stories if my memory serves me correctly.
4. I skim the new section on every visit to site; about once per day.
5. I upvote stories I find interesting or agreeable. I think this is the point of the upvote. Upvotes are where I can be entirely subjective. I upvote approximately one out of every 10 stories I read.
6. I upvote comments by the same rule as stories. I upvote approximately one out of every 100 comments I read.
7. I strongly disagree with downvoting or flagging simply because of disagreements. I don't think use of downvoting is as problematic at HN as elsewhere (e.g., Reddit), but I do feel there is still slightly excessive comment downvoting and moderately excessive story flagging (or other adjustments).
- I flag stories only if they're poorly-written and completely unrelated to tech, or if they are opinion pieces that fail to back up their assertions (two or three short paragraphs)--in those cases I'll try to comment on why I flagged it.
- I upvote stories if they're technically interesting or socially relevant; I try to make a pass through the new section at least once every day.
- I upvote comments that are thoughtful or witty but on-topic, and downvote comments that are poorly written, severely off-topic, or mean in a non-clever way (dumb trolls).
The practice of downvoting because you don't agree with something is tricky--it makes sense (I can more easily pick out comments that probably run counter to the community and thus have better entropy) but also is kind of detrimental, because it conflates "This is a bad, poorly-worded off-topic comment" with "This is a comment I find disagreeable".