"An understanding of how we categorize is central to any understanding of how we think and how we function, and therefore central to an understanding of what makes us human."
People naturally tend to categorize things. It's how we make sense of the world—one drawer for socks, another for shirts; food in this kitchen cupboard, dishes in that one. Grouping and labeling helps us find things later.
In the digital world, we create personal systems of organization with computer files and folders. Some intrinsic characteristics of information, such as file type or date, help by enabling you to sort your emails by time received or search for only PDFs, for example. But you also create folders and give files names.
All of this searching and organization relies on metadata, which is commonly defined as "data about data." Metadata are the labels used to describe objects: documents, books, photographs, MP3s, web pages, and so forth. They give us handles to grab onto when organizing information. A computer doesn't know that a photo on your hard drive is of the Eiffel Tower taken on your trip to Paris in 2005 unless you tell it so. By attaching metadata to the image, finding it becomes easier.
In the broadest sense of the word, tagging, the subject of this chapter, is not a new activity. Librarians and indexers having been "tagging" books with subject headings and keywords for years. Tags are simply ...