That's the article. Block-level would be great and let me use it to back up my VMWare virtual hard drives, which I exclude now because it would mean a 10-30 GB backup every time I started a VM. Messing with block-level is a great thing about ZFS and would allow this, but Apple's experiment with ZFS seems to have stalled for some reason.
I suspect that has something to do with Oracle now owning Sun Microsystems. ZFS has a specific type of open source license. If Oracle can sue someone over a small legal issue, they will.
At one time I had high hopes for ReiserFS, which is mentioned in the article. With Hans Reiser's unfortunate change in living quarters, I don't see any future now for it.
As far as I know Apple owns HFS+. They will probably extend it or develop something of their own.