Principles: Metadata
Metadata is simply descriptive information about data. It is used to identify key data (i.e., words, numbers, topics, categories) for each page. In a traditional library catalog this would include author, title, and subject information.
In website development metadata information is generally referred to in three ways: Intrinsic (i.e., object data such as file name, file size), Administrative (i.e., author, creation date), Descriptive (i.e., title, subject, audience, keywords).
This metadata is essential in a database-type model because it allows the information architecture to apply the structure of a relational database to the heterogeneous, unstructured information present in web sites. It also affords powerful searching and browsing capabilities that would otherwise be lost.
Controlled Vocabulary
Controlled vocabulary is a collection of preferred terms that are used for precise information retrieval. These terms are used in creating indexes, databases, and other formal tools for accessing content.
Optional Reading - Read Chapter 9: Thesauri, Controlled Vocabulary, and Metadata in Information Architecture for the World Wide Web, 3rd edition by Peter Morville & Louis Rosenfeld.
Learn More
Building a Meta-data Based Website by Brett Lider and Anca Mosoiu
Controlled Vocabularies: A Glosso-Thesaurus by Fred Leise, Karl Fast, Mike Steckel
Creating a Controlled Vocabulary by Fred Leise, Karl Fast, Mike Steckel
Web architecture: Metadata (indepth on topic
What Is A Controlled Vocabulary? by Fred Leise, Karl Fast, Mike Steckel