It is equally as annoying for people who are looking for work and place an ad to be scolded on where they place their ad.  A nice respectful reminder of where to place the ad would suffice.  I am sure that no one is attempting to annoy you, seeing as they don't know you and therefore don't care whether you are annoyed or not, but they are attempting  to generate work for themselves in an economy where there isn't much work.