What is personally identifiable information (PII)?

Personally identifiable information (PII) is any data that can identify an individual – either on its own or when combined with other information. It includes obvious identifiers like a person’s name, social security number, or email address, as well as less direct indicators such as birth dates, location data, or biometric records.

In simple terms, if a piece of information could help trace, distinguish, or contact a specific person, it’s considered PII. For marketers working with customer data, understanding what counts as PII is crucial for building trust and staying compliant.

PI vs. PII: What’s the difference?

You’ll often hear personal information (PI) and personally identifiable information (PII) used interchangeably. But there’s a subtle distinction:

• Personal information (PI): A broad category covering any data about a person that a company collects.
• Personally identifiable information (PII): A subset of PI that can directly or indirectly identify someone.

In a nutshell: PI is the full picture of someone’s data; PII are the key puzzle pieces that complete their identity.

Privacy laws also interpret these terms differently. Under the California Consumer Privacy Act (CCPA), PII extends beyond names and social security numbers to include household-level information like purchase histories, browsing behavior, and geolocation data.

The General Data Protection Regulation (GDPR) goes even further, defining personal data as “any information relating to an identified or identifiable person” – capturing identifiers as wide-ranging as cookies and device IDs.

What types of data are considered PII?

PII covers a broad spectrum of data points. Some are obvious; others are surprisingly easy to overlook:

• Name: Full names, aliases, maiden names
• Identification numbers: Social security, driver’s license, passport, taxpayer IDs
• Contact information: Home addresses, email addresses, phone numbers
• Biometric data: Fingerprints, retina scans, facial recognition data, voiceprints
• Digital identifiers: IP addresses, MAC addresses, cookies that track users across sites
• Asset information: Internet protocol (IP) or media access control (MAC) addresses
• Sensitive personal traits: Religious beliefs, political affiliations, sexual orientation, health or genetic information
• Asset details: VIN numbers, property records, financial account numbers

Even seemingly benign data – like an IP address or purchase history – can count as PII when combined with other identifiers. That’s why marketers handling customer data need to approach every data point with caution.

Other sensitive data marketers should know

It’s not just PII you need to consider. There are related categories of sensitive data with their own set of rules:

• Sensitive personal information (SPI): Under California’s updated CPRA, SPI includes data like precise geolocation, racial or ethnic origin, and genetic data. While not always uniquely identifying, mishandling SPI could result in a breach.
• Nonpublic personal information (NPI): Used in financial contexts, this refers to any data provided to a financial institution that isn’t publicly available.
• Protected health information (PHI): Regulated under HIPAA in the U.S., this covers medical records and other health-related data.

The takeaway here is that sensitive data isn’t one-size-fits-all. It depends on context, jurisdiction, and how the data is being used.

How marketers use PII

Marketers rely on PII to personalize campaigns, segment audiences, and measure results. But this comes with heavy responsibility. Once a customer opts in, their data becomes an asset – but also a liability if it’s mishandled.

Consider how PII supports:

• Personalized messaging: Using names, locations, or purchase history to tailor offers
• Behavioral targeting: Leveraging browsing history or past interactions to predict future behavior
• Campaign analytics: Tracking engagement across channels using device IDs or email addresses

But with great power comes… well, you know. Privacy breaches, data misuse, and non-compliance can erode customer trust and invite regulatory fines. Even industries that weren’t traditionally scrutinized are now expected to treat PII with the highest level of care.

Marketing tools and PII compliance

The tools you use to activate and manage customer data directly affect your ability to stay compliant. Many traditional marketing platforms require copying PII into third-party systems, increasing risk and adding unnecessary layers of security challenges.

A warehouse-native engagement platform like MessageGears flips this model on its head. Instead of extracting PII and storing it in external clouds, MessageGears connects directly to your central database. Your customer data stays where it belongs – behind your firewall – while marketers can still build and execute highly personalized campaigns.

This approach has three major benefits:

• Minimized risk: PII never leaves your controlled environment.
• Preserved privacy controls: Existing governance and security policies remain intact.
• Built-in compliance: Supports GDPR, CCPA, and other global privacy laws by design.

The result? You earn customer trust without worrying about data breaches or compliance audits.

PII is power – and responsibility

For marketers, PII is more than a regulatory hurdle. It’s the foundation of every personalized interaction you deliver. But with that opportunity comes responsibility. Mishandling PII risks the trust and loyalty your brand works so hard to earn.

The most innovative brands today are rethinking how they manage and protect customer data. They’re adopting tools and strategies that keep PII secure at the source, minimize exposure, and put privacy at the heart of their marketing.

MessageGears helps enterprise marketers do exactly that. By connecting directly to your data warehouse, you can activate PII securely – without ever moving it into a third-party cloud. That means less risk, stronger compliance, and faster campaigns that earn customer trust.

Discover how MessageGears safeguards your PII and keeps your marketing moving at the speed it should.