Thanks for the reply, I'm sorry for the off-topic discussion, it's just that I witnessed several times how a thread is doing very well (like 50 points in 10 minutes), is in the first places on the FP, then in a minute it's on the bottom of the FP, in another minute it's on the third page. So I though it must be the flaggings. Is HN's ranking algorithm public?

If a topic gets 40 comments before it gets 40 votes, it gets auto-penalized even with no flags. (too controversial)

There are also other mechanisms, such as vote-ring-detection, that can kill a topic as well.

(That is my current understanding anyway, I am not HN staff, and I am not saying whether I agree/disagree with any of these mechanisms, just stating them to help alleviate your confusion about why some topics may be doing very well and then suddenly die -- it's not always because of flagging)

> If a topic gets 40 comments before it gets 40 votes, it gets auto-penalized even with no flags. (too controversial)

I've heard about this before and it still sounds crazy to me. I comment quite a bit, and almost never upvote topics. Using the standard "other people are like me" heuristic, I deduce that the normal operation of HN involves automatically killing all the topics.

It's more likely that other people are in fact nothing like me, but I'd like to understand this a bit better.

> (2) upvotes can't be the only factor determining HN's front page; that would make it consist of controversy, gossip, and fashion all day long

That seems like an awfully low expectation of the average HN reader IQ.

It's an empirical statement that has nothing to do with IQ.