Training modules/Dealing with online harassment/slides/what-counts-as-personally-identifying-information

Handling personal information: What counts as "personally identifying information"
As previously covered, "personally identifying information" (often shorted to "PII" and sometimes expanded as "personally identifiable information") covers a fairly wide range of data that can be used to identify or trace a person in real life.

On Wikimedia projects, the category of PII includes information about a user such as phone numbers, home addresses, and workplaces, unless the user has chosen to publish that information on a Wikimedia project themselves. PII includes the real names of pseudonymous or anonymous individuals who have not made their identity public on a Wikimedia project. Private information about public individuals, such as addresses or phone numbers that the individual has not made public, are also considered PII. It also includes IP addresses and user agents of those who have not made this connection in the past.

Because the right to participate without giving away personal information is guaranteed in the Wikimedia Privacy Policy, it's usually advisable to be vigilant and conservative when dealing with anything that could be used to "out" an editor.