Comment by rsynnott

I would wonder how much of it is _generic_ job postings. Like, unless you're really huge, you probably don't need to constantly hire, say, receptionists, so you'll put up an ad for a receptionist, get a receptionist, remove the ad. If you're moderately big, you may be fairly constantly hiring software engineers, so you put up the ad and leave it there. If you're in retail or hospitality, you are probably constantly hiring people, and many of the roles are quite generic, so you're more likely again to have long-lived ads.