How do you know how old a job opening is when different sites list different posting dates?
Whenever I'm job hunting I'll frequently see a job posted within the past few days on a board like Glassdoor or indeed. I'll then go over to the company's website to find the same job listed as having been posted over a month ago. Why does this happen? Should I assume that since one of the listings is new that the position is open again, or should I go with the oldest date and figure that the opening is too old to bother applying to?