It has yielded many of our best candidates, but not yet any hires. We judge job boards mainly on the quality of candidates that it connects us with, since what happens from that point on is more a function of us and the individual candidate. So, yes, we consider it to have worked out well for us.

That said, I have my doubts about the mechanism. It seems to me that it would be more efficient to have a job board, since even a primitive one would allow candidates to better search for the jobs they are interested in. A basic job board doesn't seem very hard to set up, and we'd be definitely be willing to pay a monthly fee, because the quality of developers here is so high.