My experience is completely the opposite: I've always gotten jobs from job boards. In one case, my resume was posted somewhere (monster.com I think, many years ago) and the hiring manager saw it and liked it and called me. In all other cases, I applied myself.

I've tried working with 3rd-party recruiters, and always found them to be a waste of time, because the companies they worked with weren't good and didn't pay very well.

In contrast, I have only once in my career gotten a job via an inside contact. Of the four jobs I've had since school, three of them were with a cold application.

I think my secret is working in a specific niche, but I could be wrong.