You can’t cough these days without bumping into a ‘free’ job board, i.e., a job board where employers can post their jobs at no charge. Free job site, free Tweets, free everything. Now, there have always been a few of these boards around, but in the past year or so, it seems like they’ve been reproducing like the proverbial rabbits.

What gives? Some would argue that Free, by Chris Anderson, put a voice to a burgeoning movement: “In a marketplace with low marginal costs and many competitors, (free) feels inevitable for most digital goods.” (For a roundup of the arguments surrounding this assertion, go here).

Hmm? I guess I wasn’t the only one who choked on that: “I do agree with Anderson and Godin’s underlying point, the “freemium” model — giving away some content while offering a more valuable experience for a premium — but it’s neither a new idea nor a terribly innovative one,” said Guy LeCharles Gonzalez in a recent blog post. “The containers may change and get cheaper, but it’s the content that gives them value, and the creation and distribution of quality content isn’t free.”

So too with job boards.  Next time you see a ‘free’ job board, look at the business model. Will it endure? Is it based on providing value to employers and job seekers, or is it simply a way of grabbing some AdWord dollars for a few months? Is it extracting revenue from job seekers – and if so, does that make it a good bet for employers?

Much of the excitement about Twitter and ‘free’ in the job board world springs, I would suggest, from dissatisfaction with the ‘Big 3′ boards. Over the past decade, they’ve grown larger and more removed from their audience, increasingly fixated with extracting additional revenue from employers and job seekers without adding value, and guilty of making some bad decisions in the name of keep their stock prices up.

So how does ‘free’ resolve this dissatisfaction? Well….it doesn’t. Yes, it takes away the cost issue – sort of. Let’s say you’re given the choice of posting on Joe’s Free Job Board vs. a targeted niche board. Joe’s is free, the niche board isn’t. Joe will give you a little bit of every kind of job seeker. The niche board just gives you the seekers in its target. What happens? Joe shifts the cost of ‘free’ to you – you’re burning your time shuffling through your ‘free’ resumes and job applications, looking for someone who fits your need.

How much is your time worth? Is it free?

Mine isn’t.