Advertising arranged according to the product or service advertised, and usually restricted in size and format. The ads are "classified" into various categories such as help wanted, autos for sale, apartments for rent, etc.
Advertising placed under distinctive headings or categories of interest to the magazine reader. Designed for singe item or service announcements (rather than mass product promotion), type and style are uniform, do not usually include display, and have special insertion rates.
Classified advertising is a form of advertising which is particularly common in newspapers and other periodicals. A free ads paper is a newspaper containing only classified ads, usually grouped into an extensive set of categories.