" When you see a job posted on (insert leading job board name here) somebody paid to have it advertised there. You know where it’s free for a company to post all of their jobs? Come on, guess… If you suspected a company’s own careers website, you would be correct!"
If somebody paid for it recently, it is a strong signal they really have an opening. Jobs on companies' own sites might only be there to:
a) show to customers and investors the company is in good shape.
b) keep their recruitment buffers filled just in case.
I've been through jobs in companies with "no recruitment" enforced due to budget cuts and guess what, the job ads on their sites were still there.