Recognizing the value of sensitive data and the harm that could be caused if certain data were to fall into the hands of the wrong parties, many governments and industries have established laws and compliance standards by which sensitive data must be Pseudonymized or Anonymized.
Pseudonymization takes identifiable data and replaces it with a value that cannot be linked to a specific individual without additional information that can be accessed elsewhere. A good comparison from the literary world would be to read a collection of articles written by Mrs. Silence Dogood. You might easily observe that each article in the collection was written by the same person, but with the appropriate insider information, you might learn that the writer’s name was actually a pseudonym for Benjamin Franklin.
Anonymization is a method that replaces original clear data with a value that is both unrelatable to the original data and permanently irretrievable. Anonymized data can never be re-associated with their original data source. Continuing with the literary example above, a comparison may be Letters to the Editor authored by “Anonymous”. For a collection of such pieces, you would have no way of knowing or finding out whether they were all written by the same person or many different people. Anonymization is most often used when the original source of data never needs to be or is not allowed to be disclosed, such as in the case of a medical study.