“The company reports that its beta test of the service has attracted 400,000 professionals a month looking to connect with employers.”
Note that Work.com is (IMO) a redux of Junglee of old (remember them?); rather than employers directly submitting their listings, Work.com scrapes employer web sites for new listings (and actually does a nice job of it, including company, title and proximity drill-downs, plus mapping of the job location, etc). Ironically, you can persist queries with an RSS Feed. (This while we wait for major corps to publish job listings direct to RSS.)
The difference? Search economics. In addition to contextual-backfill, the company offers cost-per-click job listings. I finally got around to writing about this in my Future Framework for Classifieds bit 7 or 8 months ago. Good to see it starting to happen.