Concept Tags produced by the Semantic Hacker API can be leveraged to generate machine readable and displayable tags for content. These tags are significant-term tags which are derived from the content’s Semantic Signature, a semantic dictionary, and the original text.

The Semantic Hacker API concept tags are terms chosen using the highest weighted semantic dimensions found for the content text. Each of these is accompanied by a weight that describes the relevance of that term to the content and an optional position that describes the location of the term in the source content. The resulting tags are available in rel tag, tag cloud, XML, and Json formats.

A concept's weight indicates the importance of that concept relative to the topics contained in the input. In the tag cloud output format, the higher weighted terms appear larger. The following is an example of the tag cloud output format often used in folksonomy applications: