Calais is a web service that uses natural language processing (NLP) technology to semantically tag text that is input to the service. The tags are delivered to the user who can then incorporate them into other applications - for search, news aggregation, blogs, catalogs, you name it.
H. Ebner, und M. Palmér. Proceedings of the First International Workshop on Mashup Personal Learning Environments (MUPPLE08), 388. Maastricht, The Netherlands, Septiembre 2008., Seite 14-17. (2008)