PowerPivot for SharePoint. Microsoft SQL Server PowerPivot for SharePoint extends SharePoint 2010 and Excel Services to add server-side processing, collaboration, and document management support for the PowerPivot workbooks that you publish to SharePoint.
PowerPivot workbooks are Excel workbook (.xslx) files that contain large, related datasets that you build in a separate PowerPivot window in Excel, and use with PivotTables and PivotCharts in a worksheet. The window is provided through the PowerPivot for Excel add-in that you download from the web. You use the window to import large or small amounts of data from a wide range of external data sources, including corporate relational or multidimensional databases, public data feeds, Reporting Services reports, or Office documents. After you import the data, you can build relationships between disparate data so that you can work with the data as a whole.