I own a leader classified ad website in my country (not the us). You cannot imagine the pressure we get from all directions to remove categories (regulation, companies, associations, etc). The free horizontal classified ad websites are slowly dying. In the future, as a customer, you should be prepared to pay for publishing an ad with skyrocketing fees due to regulation. Classified ads will be validated (vs moderated) as regulation tend to push the responsabilities on the website owner. The categories and the variety of allowed items will decrease due to regulation and commercial pressure (You can forget reselling your 10'000USD Gucci bag after a break up).