Taxonomies :

IPTC codes are a controlled library of categories that can be generated and applied to any WCM content object as tags, that will subsequently be used by search engines to locate the object.

Internet sites such as IPTC.org provide lists of IPTC codes.

Tagging :

Tags are concept keywords or phrases associated with a single content object. For example, a Web article might include the tags Baseball, Red Sox, Tickets, Away Games, and Discounts, each leading to an index listing Web pages using that tag. This allows Web users to quickly locate all Web pages which have been associated with the term Red Sox, for example.

Tags can be used for search engine optimization (SEO), and/or to populate Tag clouds, or lists of links in a Web publication.

When you are done, select Save or Check-in (according to your selected lock mode) to save your tags.