Adddvertising appearing in newspapers (although some magazines now also feature classified advertisements) that is arranged according to specific categories or classifications. The text of the advertisements is set in the same size and style of type and the ads are usually without illustration. The three major headings are Employment, Real Estate, and Automotive, although there are many additional categories (e.g., Business Opportunities, Lost and Found, Pets, Personals, and Legal Notices). Classified advertising is usually located in its own separate section of the publication and has its own rate card. It is responsible for a major portion of the publisher's revenue. Rates are based on the amount of space (words or lines of copy) and the length of time the ad will run. The longer the run, the cheaper the per diem rate will be. Since print advertising is divided into two basic categories, classified and display advertising, classified advertising is sometimes called undisplay advertising.

Real estate

As the online classified advertising sector develops, there is an increasing emphasis toward specialization. Vertical markets for classifieds are developing quickly along with the general marketplace for classifieds websites. Like search engines, classified websites are often vertical in nature with sites providing advertising platforms for niche markets of buyers of sellers.