E-commerce companies make particular use of customer information to personalize their offers and optimally model customer needs. The data required for this is often purchased from data brokers
. The business model of data brokers is based on collecting as
about consumers as possible, processing it analytically (creating customer profiles or customer clusters) and selling it on to companies. Data brokers collect customer data from a wide variety of offline and online sources. This can be publicly accessible data such as telephone directories, but also non-public such as information from credit card companies or customer card programs. An easy way to obtain customer data is sweepstakes in which the entry information is used.
Buyer behavior on the Internet and the disclosure of personal data such as on social networks is an intensively used source for data brokers to obtain customer information. Some data brokers often operate on the edge of illegality in their data procurement and do not observe the provisions of data protection law.