From the need of bringing together advertisers and demanders, whether for products or services, was born the concept of classifieds ads.This concept would include those sections organized by categories for ease of search ads, which would consist in principle of a short description followed by contact details of the advertiser.The first appearances of these sections was in the eighteenth century, when American newspapers began to create, where for a dollar amount offered posting notices organized by categories.Gradually this advertising system was evolving around the world and gave birth to the first magazines and journals only classifieds. Many of these magazines offer ads for free for advertisers, then charging a fee for selling their their copies. In turn, we also find journals in a field, where advertisers typically professionals, pay for their ads, then the company to offer free copies to interested readers.In any case, this type of print advertising is maintenance costs (printing, storage, distribution,...),and these costs must be covered, either by the offeror or the applicant. Besides the problem of maintenance costs,are other shortcomings as ads without photos in most cases or no possibility of extending article informationor services once the magazine has been printed.Since the advent of internet, many were the sites that chose the theme of classifieds, creating a real revolution in the publication of articles and services.Having lower maintenance costs, they can offer both suppliers publication as reading the applicants free of charge for both.There are many advantages offered by this new digital age. Easy handling due to the structuring of categories, ability to view real-time date of publication,to search for items by keyword or even see the popularity of the advertiser of the item or service you're interested. Besides the advantages in terms of cost and usability, through these portals and their viewers statistics, as of today can make accurate barometersto analyze trends in buying and selling items or in the supply demand for services.According to the latest barometer registered, we know that in the past year the provinces with the highest number of transactions in Spain are Madrid, Barcelona, Valencia and Malaga. That from 23.00 hours when most number of requests and answersperformed. And the categories are more influx of home furnishings, clothing, computers, pets, and spare parts. Has also been shown as the sale of articles hasincreased sharply since the crisis stage, there are many who have needed to dispose of any property listing posting a notice on the Internet to make some extra money, as well as those who haveused this type of portal to find an item at a much more affordable.