I don't think YC is in only to 'make millions'. I also don't think pg would be writing essays or fostering a community like HN just for commercial interest, startups are a way to make the world better.
While I don't disagree with the point that pg is not out to just make loads of money -- he's obviously a really smart guy who has richer pleasures to enjoy than what money can provide, I do disagree with the stated premise that pg does not have a commercial interest in fostering a community like HN. Whether intended or not, it's probably a profoundly important component to yc's branding. Not to mention, it is an absolute goldmine for attracting developers for the startups yc funds (it's not a stretch to see jobs posts as ads of sorts -- the higher the quality of HN's userbase, the higher the quality of potential candidates). It is also an avenue for the startups it funds to gain recognition (e.g., Priceonomics recently started a blog that arguably caters to a very HN-minded audience, indeed starting a blog is an extraordinarily compelling method of advertising the existence of something).
Not that I have a problem with any of that of course -- so long as there's interesting content for me to read I'll stick around. :)
