As many as 4 in 10 companies say they have posted a job listing this year that doesn't exist, while 3 in 10 say they're currently advertising for a role that isn't real, according to a May survey of over 600 hiring managers from the career site Resume Builder. Tim Paradis, future-of-work correspondent for Business Insider, joins CBS News to explain why some companies are doing this, and how you can spot the fake postings.