Classifieds are usually one line advertisements in the print media on a day to day basis. It becomes molded to multi-paragraph ads with searchable particulars, images, videos and documents attached to it. Craigslist was the first online classifieds which used the internet to publish the advertisements posted by the users. The online classifieds were posted instantaneously whenever the user wanted to advertise his product or service instead of every day early morning prints.
Last two decades have completely changed this industry. It has grown multifold. Hundreds of thousands of websites offering online classifieds.
In the early stage, the online classifieds tend to monetize their traffic, by charging for the placement of the advertisements. But after a stiff competition, they realized that they can not survive with paid advertisements. The users tend to move away from the paid advertisements to the free ads service rendered by many.
In the advent of google's culmination as a master search engine, the purpose of the classifieds become void and every requirement was searched in the search engine itself. Google perhaps pointed to the result of such search to a particular classifieds website. This approach again encouraged the classifieds website to maneuver themselves to a google friendly to find a particular advertisement from it. This phenomenon was later called as Search Engine optimization.
In this history of evolution, the online classifieds followed a survival mechanism of posting paid advertisements to their sites which are directly proportionate to the number of visitors that website is attracting every day. If the traffic is more, that site can earn more money by advertising for their potential clients apart from the free classifieds. These paid advertisements also can be received from big ad management companies. The leader of such ad management is Adsense owned by google itself.
Some of the online classifieds
Dubai Part-time Jobs classifieds
Indian Classifieds and Marketplace