Some of the OpenOffice.org people are complaining about the ODF plugin for Microsoft Office. The developer is called a traitor by some. No matter what this means for OpenOffice, it shows the advantages of using an open, standard file format.
In the Microsoft Office world this discussion wouldn't even be possible. The OpenOffice guys may not like what's happening, but they can't stop it. This is a great showcase for how open standards prevent vendor-lock-in.