Something I've always wondered: assuming all other things (connections, community, alumni, funding, etc.) being equal, does YC win out over other "incubators" simply because of Hacker News?

There are at least two ways the HN online community could provide an advantage to YC and the YC-funded companies. I will mention the one that is most salient to me first: it seems to me that HN is an interesting online community in its own right. The guideline for submissions

http://ycombinator.com/newsguidelines.html

that a submitted link should be one that "gratifies one's intellectual curiosity" raises the tone of discussion here and brings together a lot of smart people. That, in turn, provides the first introduction to the startup community and first introduction to YC to many readers. (I discovered HN, and then YC, by reading Paul Graham essays on pg's website, and occasionally following the link over to Hacker News. I don't have a strong enough tech background to contribute to many of the threads here, but I have gradually figured out which topics--mostly mass media reporting on science or education reform--are topics to which I can contribute based on my own personal background.) I tell young people I know who are interested in entrepreneurial, high-tech business opportunities about Hacker News. They learn here about YC. At least a few of the young people I know in my town are doing serious development (which leads to coding posted on GitHub) of software-as-a-service solutions for problems they encounter in their own work. They intend to seek out YC first when they have formed co-founder groups and developed a business proposal. So I think one YC advantage that derives from HN is that YC gets early proposals from a lot of highly motivated entrepreneurs who might not otherwise have even known about early-stage funding. And the YC application form discloses an applicant's HN user name, so HN users have the chance here to establish thoughtful reputations by their comments, and YC has the mutual chance to better understand its group of applicants through each applicant's behavior here, a win-win in adding information to the appplication process.

YC startups (quite rightly) get on the front page easily, which obviously drives a lot of traffic.

You were mentioning the issue of whether a YC-funded company tends to get more visibility here on HN. Reasonable minds could differ, but I actually think that the first advantage I mention above is more powerful than the advantage you mention in your question. YC-funded startups do get much visibility here on HN, but they are not alone in that visibility. People here upvote posts if they are interesting, whether the company is funded by YC or not. The submitted post makes clear that being visible here on HN is an advantage, because readers of HN include venture capitalists and other people in the industry who can help a new company make funding and market connections that will help the company grow. But I think many of us, even those of us who are aware of which companies are YC companies and which are not, cheer on and upvote posts about any interesting new company (or new inchoate business idea), so the exposure advantage is not quite as strongly skewed toward YC companies.

I'd be glad to hear from other participants what they think about this.