The Big 3 (CareerBuilder/Monster/Hotjobs), and now job search engines like Indeed have the national job market covered. Thats why any new job board needs to be niche. Learn more by watching this 3 min video.
[youtube]http://www.youtube.com/watch?v=Ab97Og_tZS4[/youtube]
Niche boards are more efficient because of their nature. And for employers they offer a less costly way to find the targeted talent they want.