Include few if any ads. Sources always cited in the form of footnotes and bibliographies. Most often published by scholarly presses, professional societies, or universities. Articles usually indexed in specialized subject periodical indexes. Main purpose is to entertain, sell products or promote a viewpoint.
Information provided is usually of current or general interest and appeals to a broad audience.
Articles tend to be short and written in layman's terms - no subject expertise is assumed. Generally written by a member of the editorial staff or a free lance writer. Articles may also be unsigned. Usually have a slick look. Often heavily illustrated with colored photos and drawings.