That is certainly a thing. But on HN, we really do have topical trends. When an article gets popular, and piques our interest, people keep researching it. And finding related topics and articles, and those also get posted. We also see it impact the "Show HN" posts - before coronacrisis, we were seeing so many curated job postings sites that it got to be a bit of a joke. Just in the last couple week, we've see an uptick in blogging tools, and in the past couple days, an uptick in data gathering sites for police action. Trends do exist.