ZFS is widely used and still spreading. Most people are familiar with the volume-manager-like aspects, and the snapshots process. What may not be known is how you can use these features for your system administration tasks.
These features may not be unique to ZFS, but they are there, and they are useful.
* when upgrading the OS, the beadmn can be used to save your current system boot environment, then upgrade in place, giving you a safe fallback position should the upgrade fail for whatever reason.
* when upgrading the applications, a snapshot can give you a rollback position should it be needed
* cloning your favorite VMs for fun and profit
* trying to debug a build process which munges the build environment? Do it in a jail, then rollback when required
* running backups? use a snapshot instead.
* fighting CryptoLocker? snapshots might help
* do you have highly compressible data? Put it on a different zfs dataset.
* want to avoid users running code from their home directories? Apply the noexec flag!
These a just a few of the for-profit features you can use. If you're not using ZFS now, you may want to start soon