Firstly, what is the username you're claiming is invisible? I can certainly see this post.<p>But apart from that, you have, for some reason, been "hell-banned". Without seeing your posts and/or comments from around the time it happened I can't offer any suggestions or advice as to why it happened. Do note that sometimes it happens by accident. It happened to me the other day, and in a reply to an email I sent asking about it, PG said I'd been "fat-fingered" by accident.<p>With regards the algorithms, I have no inside knowledge, just deductions based on what I've seen and some experiments I've run. However, if you consistently get flagged, or get downvoted vigorously, I suspect there is an automatic hell-ban, possibly preceded by a "slow-ban" (wherein everything slows down and responds like molasses for a while). If PG was being completely honest (and I'm not suggesting he wasn't, but as a mathematician I tend to try to cover all bases) then some (and perhaps all) hell-bans are actually performed by the moderators, possible in response to flags thrown up by automated detection systems.<p>As an aside: Do you understand the effects of flags, downvotes, and their differences?<p>So if you want to know more, perform searches for "hell-ban", "flag", "downvote", "dead", and combinations thereof. You'll find plenty of discussion, and considerable complaints. For one, I think that PG has done remarkably well in keeping HN civil (although clearly not perfect) in the face of popularity, and the occasional false-positive and draconian measure might well be the price paid.