It is a pretty popular web site with a part of the technical crowd. It gets analyzed a lot [1][2]. It also gets a lot of 'spam' (since coverage on the front page of HN can send you lots of traffic [3][4][5]) HN "scores" its participants using a counter 'karma' [6] which also affects features visible to your account (well at least the down vote button) And with any 'score' there are people who score more than others [7]. And where there is scoring there is competition.
The bottom line is that certain behaviors emerge for people who actively try to achieve a 'high score' (more karma) and people who are trying to achieve 'viriality'[8] (more exposure).
It was unkind of me to point out the behavior (usually I just note it and ignore it) and for that I apologize.
Colin (grandparent posting) has a 'thing' about stuff that gets doubly or triply or more posted. I understand the annoyance, it can get annoying. But I've also noted that he posts a lot of links :-) A number of people tend to complain when their version of the link doesn't make it to the front page when someone else's done (it's a 'I'm not getting that karma whine') And generally harmless (other than it sometimes back fires and they get down voted for whining)
[1] http://blog.rjmetrics.com/surprising-hacker-news-data-analys...
[2] http://hn-karma-tracker.herokuapp.com/overall
[3] http://thestartupfoundry.com/2011/05/26/hacker-news-and-driv...
[4] http://sparknlaunch.wordpress.com/2012/07/04/lessons-learned...
[5] http://pitchpigeon.com/blog/10-lessons-learned-from-a-succes...
[6] http://pitchpigeon.com/blog/10-lessons-learned-from-a-succes...
[7] https://news.ycombinator.com/leaders
[8] Not exactly a word, but my definition would be the rate at which things spread, especially on the Internet.
http://www.jacquesmattheij.com/The+Unofficial+HN+FAQ
Bits of it are a little out-of-date, and there are some things it hasn't caught up with, but it's mostly right, and some people find it useful.
/r/KarmaConspiracy