Very rarely they would, I believe. There are thousand of applicants for each job posted. Why would a hiring manager go through a hackernews post unless the skills required are very niche.
I've never had a single email from posting in any of these threads. I think posting here just makes you look desperate. Biggest success I've had is just emailing people.
As an international contractor, I have found freelancing gigs on here. I can imagine those willing to relocate or within a major tech hub might get contacted for salaried positions. I can also tell you that is common to find someone leaving a comment similar to yours every now and then.
That's funny, I just asked the same thing. Usually employers aren't interested in people looking for jobs, they're interested in people that already have jobs.Maybe in an ideal world it would be otherwise, but we don't live in that world. When you don't have a job, you're kinda fucked.