Please click on the 'Vote as Helpful' button! With Office being used on more than 1 billion Macs and PCs worldwide, you can work with practically anyone you want, how you want, wherever you want-with no worries. knowing that Office for Mac is most compatible with Office for Windows. I haven't seen anything explicitly mentioning file structure compatibility, but since they are going on about feature compatibility and collaboration with PC user, I would guess that the new files are compatible. This article talks about 'look and feel' compatibility between PC 2010 and MAC 2011 for the ribbon and features.
