Ask HN: Got 'shadow downranked' on Hacker News

When commenting on HN, the comments usually sticks at the top postion for around ten minutes in order to get some visibilty. Then, the gravity pulls the post slowly down except it got many upvotes.

Since I posted that Instagram Ads are a joke performnace-wise all my comments afterwards are always and instantly below the first comment without never touching the first position. Always and even if the top comment is from a new account w/o any karma.

Why? Some hidden semi-ban? And if yes why?