Explanation should include

• the term data collection as the process of gathering pieces of information
• active vs. passive
• informed consent vs. no consent
• the types of sources where data can be collected
• first- and third-party cookies
• device fingerprinting
• information gathered by social networking sites
• information collected through search engines
• information provided voluntarily in exchange for services or access to services (e.g. user agreements)
• data brokers
• biometrics.