Common Tag is an open tagging format developed to make content more connected, discoverable and engaging. Unlike free-text tags, Common Tags are references to unique, well-defined concepts, complete with metadata and their own URLs. With Common Tag, site owners can more easily create topic hubs, cross-promote their content, and enrich their pages with free data, images and widgets.
The companies involved in the development of Common Tag — AdaptiveBlue, DERI (NUI Galway), Faviki, Freebase, Yahoo!, Zemanta, and Zigtag — offer services that help publishers get started.
