[dan_bk]

Who goes on such a site? Jobseekers. Which jobseeker has an incentive to retweet a job s/he finds interesting? Usually YOU want the job you find interesting. Why retweet it when this makes it harder for you to get the job?

[PEntremont]

Jobseekers are not expected to retweet. Company stakeholders and relevant jobseekers friends are.