Just because they give them out for free (to a very small specific group of companies) doesn't mean they don't have value.

Oh yes they certainly have value - but Those job listings aren't ads that pay for servers and bandwidth for hacker news.

Depends how you look at it.

Whether that value directly pays for servers or intangibly-or-directly increases their own startups' value doesn't seem like an important distinction.

Well, they are YC companies so they pay YC with a pretty significant portion of their equity.