Modern advertising technologies rely heavily on users' personal data to help advertisers better sell their products, but the data sources used by ad tracking technologies violate users' personal privacy. Ad tracking technologies collect specific personal information from users, such as name, address, browsing habits, bank card number, etc. Some technologies can also track users across devices and collect geolocation data. Third-party ad networks track us on different websites. Some software will even use microphones to record audio without our knowledge and then push us specific advertising content based on the recording. Companies that collect personal data can also sell this data to other companies, and our personal data is also at risk of being compromised.