Craig's List, who had previously said they'd cut down on prostitution ads, still holds the title "single largest source of prostitution". In Chicago, at least, according to a Cook County sheriff, who has noticed, first-hand, that the place to go to find a hooker is Craigslist. Looks like "your mom" is falling further as the correct answer to the question: "where do I find a hooker?", but Craigslist is nowhere near as funny.