Structured data refers to information with a good level of control and organization—for example, a “date” value in an “expiration date” field. Structured data is usually found in a controlled data environment with inherent meaning and purpose. 

Unstructured data lacks that control and meaning; it offers a confused sense of purpose and requires analysis or interpretation to restore meaning. Using the example above, if a “date” is discovered with no field in which to provide that control and structure, what does that tell you? The interest is in wrangling all that data to create a more structured sense of purpose for the content in your organization; it makes information more relevant, palpable, understandable, and usable.