(1) Commonly used in blogs, site authors attach keyword descriptions (called tags) to identify images or text within their site as a categories or topic. Web pages and blogs with identical tags can then be linked together allowing users to search for similar or related content. If the tags are made public, online pages that act as a Web-based bookmark service are able to index them. tags can be created using words, acronyms or numbers. Tags are also called tagging, blog tagging, folksonomies (short for folks and taxonomy), or social bookmarking.
(2) The act of placing RFID labels bar codes on items is called tagging.