Personally identifiable information, aka PII, is any information that could be used to trace an individual’s identity.
Common personally identifiable informations are :
social security number (SSN)
driver’s license number
others identification numbers
detailed street address
persistent IP address
Less specific informations can be considered as PII when combined - last name + local data for instance.
Cookies are not PII but may content or be tied to personally identifiable informations.
Privacy regulations limit the use of PIIs in digital marketing context and more specifically in digital advertising targeting processes.
In some contexts, when collecting data, marketers and advertisers have to strip off PIIs to preserve anonymity of consumers. The process is called anonymization.