The selection of interoperation areas and their prioritization must begin with user need and requirements. Many 
application projects have been initiated between two or more Grid projects and it is important to use these types of 
projects to drive interoperation. A set of application and use case scenarios that motivate the need for interoperation 
must be documented. Many of these were seen during the SC05 conference, where a large number of application projects 
showed use of multiple grids..