This is a repost of something I just wrote as a comment on OSNews:
Shadow copies, at least in the current Volume Shadow Copy implementation, are most definitely NOT “exactly” the same thing as Time Machine. While VSC is very similar, it’s designed to do snapshots at certain times. This is fine for most restores, but in general, if you modify a document several times, you only have the version at the time of the snapshot. As I understand Time Machine, it does a snapshot at modification time, so you have each modification.
This might seem like a marginal difference, but in reality, it’s anything but trivial. This is a world of difference and nothing like this currently exists in a usable form in the base install of ANY consumer OS today. So while it may not be a new idea, it certainly IS innovation.