A few months ago, I read a blog post by Ken Sherrif [0] which explains (and shows graphs) that some submissions have their scores automatically penalized based on domain:

> Some submissions get automatically penalized based on the title, and others get penalized based on the domain. It appears that any article with NSA in the title gets an automatic penalty of .4. I looked for other words causing automatic penalties, such as awesome, bitcoin, and bubble but they do not seem to get penalized.

> I observed that many websites appear to automatically get a penalty of .25 to .8: arstechnica.com, businessinsider.com, easypost.com, github.com, imgur.com, medium.com, quora.com, qz.com, reddit.com, rt.com, stackexchange.com, theguardian.com, theregister.com, theverge.com, torrentfreak.com, youtube.com. I'm sure the actual list is longer. (This is separate from "banned" sites, which were listed at one point.

Page ranking also decays with time, and I think also once you reach a discussion threshold. (I haven't re-read the entire article as thoroughly just now.) I highly recommend reading the article, as it's VERY interesting and well presented.

[0] http://www.righto.com/2013/11/how-hacker-news-ranking-really...

I understand there are weighting penalties, where points for certain domains only count as e.g. 40% of their real value.

Penalities mean that the link requires significantly more upvotes than usual to hit the front page, and if it does hit the front page, it won't stay there for long.

A good description of the math behind penalties (and a list of some penalized domains) is here: http://www.righto.com/2013/11/how-hacker-news-ranking-really...