There is. There is banning and shadowbanning, which includes mechanisms where whatever stories someone posts are "dead" on arrival. HN has robust mechanisms against spam. Re "manipulation" I'd think one person's manipulation is another person's posting interesting stories, but as was said, if someone's submissions get flagged enough, it will get attention and their posts will be killed if deemed spam. Overall I think it's more common just to see posts that people disagree with or read into versus actual "manipulation".
Also, the concept of manipulation is very insulting to the readership. Maybe it's sometimes warranted, but on HN of all places, I think people can debate, judge, and flag on their own if they think something is being manipulative.
Also, the concept of manipulation is very insulting to the readership. Maybe it's sometimes warranted, but on HN of all places, I think people can debate, judge, and flag on their own if they think something is being manipulative.