Software

With Excel Viewer, you can open, view, and print Excel workbooks, even if you don't have Excel installed.  I suppose it's something like how Adobe's Acrobat Reader works. Really smart too. More people will be willing to pass around Excel files.

You can also copy data from Excel Viewer to another program. However, you cannot edit data, save a workbook, or create a new workbook. Microsoft is aware of the open source community and I can see that they want people to use their...