Comment by llm_nerd

All 100% true, it is more muted, but another effect that happens is that when a source is a sure thing on HN, it's self-reinforcing. People start watching those sites for new entries and submit them, and HN's automatic behaviour is that if you submit an entry that already exists, it just upvotes the existing entry.

Get dozens of people watching the hot blogs for content, each running to submit it, and in an instant it's to the front page and the reinforcement redoubles.