Very ignorant, Traderszones. I have found better companies posting on Craigslist compared to CareerBuilder, for instance (talking about finance and real estate).
In fact, I have found craigslist ads for the best real estate companies in the city and country, both commercial and residential. The fact is, so many people use craigslist now, that is where much of their target is. I think Yahoo is a terrible job search although I guess they have an exclusive Barclays Capital account. Monster I like myself. There are some niche finance related ones that I was not too impressive with.
Overall, these companies know that Craigslist probably produces the most traffic for good or for bad, so they have to advertise on it if they are in need.
Sure, there are some BS ads and companies, but it doesn't take much to figure out which ones they are.