Whether portable or installed, Office 2007 introduced several revolutionary changes to the Microsoft ecosystem:
SoftMaker offers a free, portable version of its Office suite. It claims better compatibility with Microsoft file formats than LibreOffice. The interface can be switched to classic menus or a Ribbon similar to Office 2007.
The paper is interesting because it documents how to do something Microsoft explicitly designed to be impossible—and in doing so, it inadvertently explains how modern app virtualization works.