Specifically, even though the number of job openings is increasing, the number of unemployment workers remains unusually high. There appears to be a mismatch between the new jobs and the skills of the existing workforce.
As the New York Times puts it:
"Plenty of people are applying for the jobs. The problem, the companies say, is a mismatch between the kind of skilled workers needed and the ranks of the unemployed."
Part of the story, in my opinion, is the reorganization of work catalyzed by the increasing use and power of IT.