Always-on distributed spreadsheet mashups

We present a platform that supports the creation of distributed data Mashups, implemented through the composition of multiple spreadsheets. The basic idea is to link cell ranges belonging to different spreadsheets in such a way to come up with a distributed spreadsheet. While such a behavior is already supported in private file spaces, our platform extends the operating principle and the functionality to the Internet in a secure way, using a SOA infrastructure as a communication bus. The platform consists of a client component, installed as a Plug-in in spreadsheet applications, and of a server component, accessible as a Web Service, that orchestrates the data exchanges among the client spreadsheets. One of the most original functionalities provided by the platform and described in the paper is that of guaranteeing the propagation of values along chains of linked spreadsheets even when some of the component spreadsheets are off-line.In addition to the description of the platform the paper also includes the description of a Spreadsheet Mashup framework specifically suited to hierarchical organizations such as those of enterprises. The architecture of the framework is presented in the light of a real-life example.