We constantly see this in trying to figure out what kind of stories are supposed to be submitted to HN.
Does it really make sense for a person like Maciej Ceglowski to be permabanned from HN? https://twitter.com/pinboard/status/111332316458135553. I think it's a shame, partly because I think he's a smart guy with a fresh view on things, but also because I don't think the reasons for banning him are very compelling.
You can't have poorly-defined rules and opaque moderation at the same time. You'll see why, when you incur the wrath of one of pg's moderation scripts for no apparent reason.
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EDIT: As an aside, to give an idea of what a fucking pain being (inexplicably) hellbanned is, picture all your Hacker News bookmarks no longer working, because you've been banned from the entire site.