Happenites,
I've recently read somewhere that there are an estimated 40k-100k job boards
in North America. Here's a list that purports to contain the top 100.
http://www.internetinc.com/top-100-job-site-niches-2009
Good Hunting,
Rick Stomphorst
rstomphorst@gmail.com
www.linkedin.com/in/rstomphorst
www.Twitter.com/StompR