Why job ads don't work?

Many job postings today have very little information and appeal. Job seekers, particularly the top talent, expect the job ad to be informative and compelling. But many job ads lack enough information and fail to answer the questions that arise in the job seekers’ mind and even worse, the job ads deliver the wrong message. Hence the job seekers are unable to evaluate the opportunity and make an informed career decision.
Another reason why job ads don’t work is many companies continue to invest in ads that do not yield the expected results. The reasons may be attributed to their habit (posting the job ads in the same sites irrespective of the results), financial constraints (fixed budget or the company would have a tie-up with a particular job board) and awareness (There are thousands of job boards and career portals. Posting a perfect job ad in a wrong site will not yield the expected results.)
So it is essential for recruiters and hiring managers to ensure that they post effective job ads at the right places.