Sure, feel free to ask anything you're curious about. The only reason I know the answers is because I've been around since day two across various accounts.

> So does the original author of the comment see "[dead]"?

Nope.

> Does it happen automatically if the author is banned/shadow banned?

Yes, all submissions and comments from a banned account are automatically killed.

> Why/how are so many 'New' submissions 'DOA'?

There is a banlist for domains in addition to accounts. Any attempt to submit a link to a banned domain will be killed.

Interestingly, news.ycombinator.com is banned in order to prevent meta-submissions. If you're curious what someone sees when they submit a banned post, submit e.g. this comment.

> Is there anywhere that explains this so I never have to ask these questions - and others - again?

Nope. :) It's an evolutionary process that's been going on for 9.7 years. http://www.paulgraham.com/hackernews.html

There are at least four other ways that a comment can become dead: if it's a dupe (try submitting the same comment twice), if it's flagged by multiple users (around three or four, I think?), if a moderator manually kills a comment, or if someone is posting from Tor under a brand-new account.

In the case of a dupe or a flag, you'll see [dupe] [dead] or [flagged] [dead] respectively. That's how you can tell why a comment is dead: if it's just [dead], either a mod killed it, it was posted by a banned user, or was posted from a Tor user. If the user's name is green, it's probably a Tor user.

In this case, they were obviously banned because the comment was only 24 minutes old when I replied. Nowadays, when a moderator kills a comment manually, they will usually leave a reply stating the reason. Since there was no reply, I suspected the user was banned.

This brings us to one of HN's most interesting features: the vouching system. If you have a certain amount of karma, I think a few hundred points, then you can cause a comment to go from [dead] to alive. The reason this was implemented is because sometimes a banned user posts an informative or harmless comment. These comments would provide value to the community.

To vouch a dead comment, you must first be able to see dead comments. If you go into your profile, you'll find a setting called "showdead" which you can set to true. (By default, no one sees dead comments.) Then to vouch, click on a dead comment's timestamp. You'll be taken to a page with a "vouch" link.

I don't know how it is for other users, but for me, clicking on "vouch" always resurrects the dead comment. I.e. only my own vouch is necessary. I assume it's the same for other users.

This is a serious responsibility. The moment that people start vouching crap comments is the moment dang will have to rework the vouching system. HN brings a bit of joy to my life, so I like to go out of my way to vouch dead comments that are high quality, and then read through the user's previous comments to see whether they were banned and why. 95% of the time, I say nothing to them. Users were almost always banned with good reason. In the case where you spot someone who was banned for seemingly no reason, the user was almost always involved in abusing the site (voting with multiple accounts, etc).

This user happened to be the exception to that. They were banned 6.2 years ago with seemingly no reason. Perhaps they were involved in some sort of abuse against HN. Or perhaps they were posting from a shared IP address and happened to get be mis-identified. Either way, 6 years is certainly enough time for them to appeal their ban. Besides, I like the idea of someone coming back to the site and being welcomed.

The HN team is very responsive and quite reasonable, so usually if you send a sincere apology and promise to behave then you'll be given another chance.

It's been pretty fascinating to watch the moderation process evolve along with the community over the years.