I have doc and ppt files with equations in them created by Equation Editor. I created the files in Microsoft Office X for Mac Service Release 1. I am thinking of switching to Office Mac 2008 as that is what most of my students use. What will happen to the equations?
In Windows, equations created in Word 2007's equation editor get turned into un-editable graphics in PowerPoint 2007; this was fixed in Office 2010.
I imagine the OSX versions of Office around that time fixed the problem too, so for your question: "likely depends on version number."