The discussion begins with a mailing list message called Interesting Behavior of OS X, in which Steven Edwards describes the discovery that Leopard apparently contains an undocumented loader for Portable Executables, a type of file used in 32-bit and 64-bit versions of Windows. More poking around revealed that Leopard’s own loader tries to find Windows DLL files when attempting to load a Windows binary.
So let’s not get all excited too quickly. Like the article says, this could happen and it could end up going no where. Also, would this mean Macs would be more susceptible to viruses? (My gut says no, the reason Windows machines are so vunerable is because .exe files can autorun, I doubt they would be allowed to autorun on OS X).