Image: Bryan Loar's Current Jobs Folder
It's amazing how many different resources are out there and how they could easily be missed. Not knowing where to look, as Mary Pergander points out, is certainly a danger.
Some services like ALA JobLIST and LISjobs.com (and Chronicle of Higher Ed. to some extent) allow users to create RSS feeds specific to their preferences. However, there are many lesser known state-based resources that could be easily overlooked. One helpful source to use in order to uncover these resources is Library Job Postings on the Internet.