Microsoft has switched from using binary file formats (.doc, .xls, and .ppt) to using the Open XML formats (.docx, .xlsx, and .pptx). Each Office application that uses the new file format— Microsoft Office Word 2007, Microsoft Office Excel 2007, and Microsoft Office PowerPoint 2007—by default stores most of the document content in the Open XML formats. Other document components, such as embedded code, comments, macros, charts, images, tracked changes, and document metadata, are stored separately within the file. Office 2007 zips each component, then zips the entire document (this process is transparent to the user). The resulting files (i.e., the document file and associated component files) in Open XML format are significantly smaller than their binary ancestors. For more information about the Open XML format, see the Microsoft article “Introducing the Office (2007) Open XML File Formats” (http://msdn2.microsoft.com/en-us/library/ms406049.aspx).