Are there any information/discussions about the "censoring mechanisms"?
It doesn't happen too often, however. The community here usually has pretty high commenting standards, and there's peer pressure that encourages good behavior.
They of course aren't notified at all, so they're quite happy to keep adding comments to the site, all of which stay at 1 point and never get replied to (or even read by anyone except those with showdead on).
Since there's no messaging system on this site, if they haven't bothered to add any contact information to their userpage then there's no way to let them know.
I occasionally see these folks posting some pretty thoughtful comments while auto-dead, too.
However, this has been a subject of discussion here a few times, and nothing has changed; I don't expect it to.
I do expect that this site will be banned soon too.
I'm not saying that that's the best solution. A mefi-like $5 cost to join might be better, but then a) PG has to implement the payment stuff, and b) some people will complain about us charging nontrolls to get accounts.
It's possible that there could be some system where if, say, 5 people with at least 200 karma will vouch for you, it's free, but then there's even more complicated code that needs to get written, and people will complain that you can only join HN if you pay or are part of the "in crowd" that know lots of HNers.
I actually think that could work really well though. If for the first month/50 karma, those people were supposed to moderate the sponsorees comments and give them feedback on what they're doing well and what they're doing badly, we might have a lot fewer complaints about all those noobs that are ruining our site.