The Internet changes everything, because it is not only a medium but a marketplace. This creates an incentive to supply the identifying information, in exchange for the ability to access the premium tier. Periodicals that operate or sponsor trade shows and conferences create another, super-premium, database of people who registered for, or at least inquired about, the event. Controlled circulation is very important in B2B publishing. Almost every publication has had the experience of getting printed or online registrations from individuals who are interested in the publication but don't qualify for a free subscription.
Data mining makes it possible to make productive use of their demographic information.
The publication can notify such people that they don't qualify for a free subscription, but can purchase a subscription. Non-qualifiers can be given information about publications for which they do qualify. If there are enough of them, it may be a signal that a new print or e-mail publication, or a new Web site, should be created to meet their needs. Both of these databases are potentially interesting to advertisers, and potentially profitable for the publisher. Data mining is the science and process of aggregating and interpreting an organization's data, in order to find patterns that are not only intellectually valid, but also useful in practical terms.