Categorize
Categorize the content into a set of predefined categories.
The API call can be used to compute a list of predefined categories that summarize your content. There are two taxonomies of categories that can be used - dmoz and news.
The dmoz taxonomy contains over 5000 categories and can only be used for documents in English language. It is organized into 3 levels and go from more general to more specific topics.
The news taxonomy contains only 8 top level categories commonly used to categorize the news content, but can be applied on any language.
The categorization into both taxonomies can work well only on documents of decent size (like news articles).
The iptc subject codes contain over 1,000 categories organized into 3 levels. The taxonomy is maintained by IPTC standards body of the news media.