Net60 specializes in response lists, which consist of people who have demonstrated an interest, purchased or inquired about a specific product or service. These lists are usually based a buying history, membership clubs, subscriptions to newsletters or organizations, sweepstakes, infomercials, catalogs, trade show attendance, etc.
Compiled files, by contrast, are large databases that have been generated from phone books, yellow pages, directories, web crawlers, credit files, government agencies, and other public records such as the county tax assessor files and other public domains.
Compiled lists frequently include considerable demographic data (job title, company size, telephone numbers, etc), and often provide the best means of reaching large groups of specific audiences. But response lists are typically of a higher quality, since they are based on the behavioral aspects of the individuals.
A response-generated list will generally outperform a compiled list, and can be expected to be more expensive as a result.