OpenCalais is an open source project that creates rich semantic data by using natural language processing and other analytical methods through a Web service interface. It is a simple explanation for a piece of powerful software. OpenCalais was originally part of ClearForest, but Thomson Reuters acquired the project in 2007. Instead of marketing OpenCalais as proprietary software, Reuters allowed it to remain open. OpenCalais has since become valued metadata open source software that is used on blogs to specialized museum collections.
There are many notables who use OpenCalais and a sample can be found on “The List Of OpenCalais Implementations Grows.”
OpenCalais is excited about the new additions to the list: