PG's answer is of course canonical, but as an outside observer, I believe it is incomplete.
The unstated hidden reason comments are disabled is because comment threads often dilute the message of the posting.
Threads can digress and accentuate negative, minor, or emotional/controversial distractions. The postings are a favor to the listing company. If that company prefers just "here's our message, contact us", with no risk of defocusing tangents, then that's the right favor for YC/PG to grant.
It may also be better to decide up front, "we'll give up the comments, good or bad", than to allow comments, and get a few that are so unproductively snarky they create a back-and-forth with critics, or that trigger premature speculation about things strategically left unsaid, or that prompt a later censorship decision (with its accompanying distracting gripetails).
As I've explained before, jobs aren't stories. Though jobs get displayed like stories and get inserted into the frontpage feed along with them, they're a different type of object. The reason I didn't give them comments was that I thought of them as ads, not content.
I would like to see comments on job postings. I don't consider them ads, to me they are interesting content. Even if they were ads, what's intrinsically wrong about enabling comments in ads? There's already a system in place for dealing with inappropriate comments and it works well.
If HN allowed comments on YC job posts, people would use the comments to post job ads for their own companies ("we're doing something similar, &c &c, contact us at &c &c"). This would significantly dilute the value of the YC job ads.
The inevitable discussion about how we could just have an etiquette of not doing that, or a guideline for not doing that, or a new kind of flag button for that, or or or, will just serve to illustrate how much simpler a solution just not allowing comments on those posts is.
These posts aren't hurting you. My bet is most HN people actully think they're a benefit of HN --- early access to YC jobs! This is a fake controversy. Can we think about tolerating the YC job ads in terms of "least we can do for running HN"?
I think they are a benefit to HN, and I think that allowing comments would be even more beneficial as I stated in my comment below. You may be right, but the people wanting comments may also be right but we'll never know unless the experiment is actually run and I thought a large part of HN was experimentation.
This most recent case suggests another problem with adding comments to jobs, at least for startups that hadn't launched yet: a few jerks would make a game of trying to out them. Which would mean such startups couldn't be as specific in job posts, lest they give away something that identified them.
I don't think it's reasonable to conclude that people who endeavor to figure out and post the identities of startups who post jobs are jerks. You make a fair point about why they shouldn't do it, and I think you're right to discourage it. Curiosity, however seems like a more probable motivation than malice.
I don't think whether comments are allowed will make a difference when there is suitable mystery/curiosity. The recent case also illustrates this: other posts in this forum or others will be spawned to try to reason an identity out.
A posting anywhere with enough specific info to prompt applicant interest will prompt other observers to fill in the details. It's true for Google, Apple, Facebook etc. – so it will be true for self-identified YC startups who tout their impressive metrics as well.
I posted the thread on asking what the startup was and I certainly didn't mean to be a jerk towards the new company. I was mostly curious because they got so much traction so fast and was willing to learn on how they achieved it. I apologize pg and YC W11 startup.
