MicrosoftTM released OfficeTM 2007 Service Pack 2, which contains various improvements to the latest version of Office. Among them, one is particularly important: the capability to read OpenDocument Format, the same format used by default by OpenOffice.org, NovellTM OpenOffice (go-oo), and KOffice, which has been approved as ISO standard. This addition empowers you to choose which format to use, in order to be backwardly compatible, and at the same time make your document easier to share, independently from the platform the receiver of the document is working on. In addition, the format has been adopted or is under adoption in various countries, and further details can be found here.
Edit (Apr 29th) – Some example of what is the compatibility level of the filter added with SP2 is shown here. Details on Word, Excel and PowerPoint features are summed up too (click on the application name).