Over the years I have quite often used nationwideadvertising.com for quickly testing online/offline publications for ad response as a preliminary to launching new niche marketing campaigns. Although direct selling of products through classified ads seldom is profitable on the front end, it is a relatively inexpensive method for generating leads and/or testing publications for conversion rates. For example, acceptable conversion rates from these initial tests would result in a series of escalated advertising options including article syndication. This website claims to have a database of a "million" newspapers and magazines, most of which also have online components.