[kevinskii]

Sure, some HN comments and their ensuing discussions may be completely unrelated to the posted topic. I've learned a lot from these over the years, and I'm happy to ignore the ones that I don't care about.

But just as there is now a guideline against making irrelevant and unsolicited nitpicky website design complaints, it would be useful to have a guideline against "I thought the article would be about X" types of comments as well. These are similarly pervasive, and of similarly low value. It might be different if they started a discussion about X (power transformers in this case), but they almost never do.