Cognos Mashup Service
Cognos Mashup Service is a web service that ships along with Cognos SDK (Software Development Kit) for Version 8.4.1 onwards. While Cognos SDK supports report authoring through programming, the Mashup Service is purely meant to run reports, access the report output, and expose the contents to other business applications in the UI and workflow.
Partner services talk to Cognos Mashup Service (CMS) using a REST or SOAP request. The contents are accessed in the XML, LDX, HTML, or JSON format. You can find more information about this in the IBM developerWorks library.
Some popular usages of CMS are embedding Cognos report contents into Google Maps, Google Earth, Adobe Air, and so on. Refer to the following link for one such example:
http://www.ibm.com/developerworks/data/library/cognos/page486.html
You can find more information and examples in the IBM developerWorks library and other discussion forums.