Every app you use collects data about you. Who owns it, who can see it, and how it is used are some of the biggest questions in computing today.

What data is collected

Digital services can gather:

  • What you provide: name, email, photos, messages
  • What your device reveals: location, device type, contacts, browsing history
  • What is inferred: interests, habits, and predictions built from your activity

Personally identifiable information (PII) is information that can identify a specific person, such as a name, address, or ID number. Companies use data to personalize services and sell targeted ads. Governments and researchers use it too, sometimes for public good, such as tracking disease outbreaks.

Risks to privacy

  • Data breaches: attackers or mistakes expose stored records.
  • Tracking: cookies and other trackers follow activity across sites.
  • Re-identification: removing names does not always make data anonymous. Combining a few facts such as birthdate, zip code, and gender can single out an individual.
  • Overcollection: keeping more data than needed raises the harm if it leaks.
  • Metadata: details like when and where messages are sent can reveal a lot even without the content.

Sharing on social media can also be permanent. Once something is posted, copies may exist that you cannot delete.

Protecting privacy and security

  • Share only what is needed, and read what permissions an app requests.
  • Adjust privacy settings and review them regularly.
  • Use strong, unique passwords and multi-factor authentication.
  • Use encryption (HTTPS, encrypted messaging) for sensitive information.
  • Be cautious with public Wi-Fi.

Organizations should collect minimal data, encrypt it, limit who can access it, and be clear about how it is used.

Rights and laws

Laws increasingly give people rights over their data. Examples include the EU’s GDPR and California’s CCPA, which can let people see what data a company holds, request corrections or deletion, and opt out of some sales of data. In the United States, COPPA places rules on collecting data from children under 13. Privacy law differs by country and changes over time.

Privacy and security are related but not identical: security protects data from unauthorized access, while privacy concerns what data is collected and how it is used, even by authorized parties.

Check your understanding

1. Which is an example of PII?

  • A random number
  • A person’s home address
  • The weather
  • A public library name

Answer: A person’s home address. PII can identify a specific individual.

2. Why can “anonymous” data still be a privacy risk?

  • It is always encrypted
  • Combining it with other data can identify individuals
  • It is too small
  • It cannot be stored

Answer: Combining it with other data can identify individuals. This is called re-identification.

3. What is the difference between privacy and security?

  • They are identical
  • Security protects against unauthorized access; privacy concerns how data is collected and used
  • Privacy only applies to companies
  • Security only applies to passwords

Answer: Security protects against unauthorized access; privacy concerns how data is collected and used. Both are needed.

4. Which practice reduces privacy risk for an organization?

  • Collecting as much data as possible
  • Collecting only the data it needs
  • Sharing passwords widely
  • Never updating software

Answer: Collecting only the data it needs. Less stored data means less to lose.

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