Websites collect data through cookies, forms, and tracking pixels for advertising and profiling.
Data about you is collected in three ways. Explicit collection: you fill in a form, create an account, or make a purchase. Passive collection: tracking pixels in emails, cookies on websites, location data from apps, and metadata from device use record your behavior without active input. Derived collection: companies infer sensitive attributes — political affiliation, health status, income — from patterns in your behavior data.
A tracking pixel is a 1-by-1 transparent image embedded in an email or webpage. When your email client loads the image, it sends your IP address, device type, email client, and the exact time you opened the email to the sender's server. Most newsletter services use these to measure open rates.
Data brokers aggregate these streams into profiles that may include your name, address, employer, salary range, purchase history, health indicators, political views, relationships, and daily routine — all compiled from sources you never directly provided that information to.
You can opt out of data broker profiles. It requires submitting opt-out requests to each broker individually — a time-consuming process. Services like DeleteMe or similar in your region automate this for a fee. Preventing your information from entering these databases in the first place, by being selective about what you share and with whom, is more efficient than opting out after the fact.