My company posted 3 job listings 3 weeks ago -- you can look at my posting history to see the jobs I posted here on HN. So far we've gotten about 120 responses in total. The majority were for the Software Engineer and VP/Engineering positions; very few responses for the Operations Engineer job. Most of the software and ops candidates were so-so, though the VP candidates were quite a bit higher caliber.

Most of our candidates came from Craigslist; we advertised in 3 cities and got quite a few candidates from all 3 cities. We also got a few good candidates from the monthly HN thread. We posted to a few inexpensive job boards like Startuply and Startups Hiring but we didn't get many responses. We haven't tried any of the more expensive job boards like GitHub and Stack Overflow because the ROI isn't very clear. Those sites are pretty expensive, especially with 3 positions open. I'd love to hear more from others about whether those are actually worth the money.