I think at the core of it all, Hacker News is about discussion and conversation, and sharing job opportunities are a by-product of that, not the main focus. By

I think at the core of it all, Hacker News is about discussion and conversation, and sharing job opportunities are a by-product of that, not the main focus. By cluttering up the feed with auto-generated content on a more frequent basis, the value of all the other good stuff we come to read would be diminished. Not to say that 'Who's hiring?' isn't useful, maybe we just don't need it that often