I've read through this thread, and I've read through the previous Stallman interview ( http://interviews.slashdot.org... ), but I fail to find any of his answers. Am I just plain stupid (bait!) or are the answers posted somewhere else? Does he answer under a slashdot ID or as AC?
The Known Issues and Features in the Works page for ZFS on MacOSforge explains the situation pretty well. Integrating ZFS into MacOSX isn't just a matter of creating a device driver. Time Machine, Finder, Spotlight and other core OS products needs to support ZFS features explicitly, since ZFS behaves a lot differently from HFS+.