What do you mean by "Backward compatibility"? If you mean that all software that currently runs on our Macs now won't run with 8: it seems as if people have fallen for another one of the media's many blunders conscerning Apple. Apple, acording to TidBITS is going to keep all software that doesn't use undocumented System calls running on 8. Read the attached TidBITS article for more info.