There are very niche job sites that focus on specific technologies. Are these places more effective at connecting employers with qualified candidates than the more conventional and less focused job sites?
I don't think so.
To be effective, a job site primarily has to be well-known to potential employers and job-seekers. The more "niche" the job board is, the less known it will be.
Also, I'm not sure it makes sense for employers to look only for people experienced with certain technologies: In most cases it's better to take (e.g.) a good C# programmer and teach her Java, than to hire a mediocre Java programmer.
Most importantly, I think these sites are solving the wrong problem. Filtering companies/job seekers by skill or location isn't the problem. Every job site can do that, but still we have the situation you describe. I think the real problem is that job sites have too little and the wrong kind of information about potential employers/employees. On a typical job site, job seekers can see:
- how big the company is
- what kind of products or services the company offers
- what kind of skills are required for the job
What they really want to see are things like:
- Whether the task they're expected to do is interesting? Challenging?
- Whether the coworkers are fun to work with
- Whether the bosses are fun to work with
But no employer will admit on a job site that you're expected to do boring work with no-fun coworkers under pointy-haired bosses.
From the employer perspective, things aren't much better. Job seekers will tell things like you:
- What kind of degree they have
- How many years of experience they have
- What kinds of technologies they've worked with
What the employer wants to know about a job seeker is (among other things):
- Whether the candidate can solve complex problems, reliably, on her own
- if she can work well in a team
- if she really has N years of experience or just the same year of experience, repeated N times.
But after reading many "interview"-questions here on stackoverflow, I've come to the conclusion that it's more or less impossible to answer these questions from a job application or even a job interview alone.
I don't have a solution for that problem, either. But I don't think concentrating on niches can be the solution.