Just for fun I had a look at the popcon number of ZFS related packages in Debian, and was quite surprised with what I found. I use ZFS myself at home, but did not really expect many others to do so. But I might be wrong.
According to the popcon results for spl-linux, there are 1019 Debian installations, or 0.53% of the population, with the package installed. As far as I know the only use of the spl-linux package is as a support library for ZFS on Linux, so I use it here as proxy for measuring the number of ZFS installation on Linux in Debian. In the kFreeBSD variant of Debian the ZFS feature is already available, and there the popcon results for zfsutils show 1625 Debian installations or 0.84% of the population. So I guess I am not alone in using ZFS on Debian.
But even though the Debian project leader Lucas Nussbaum announced in April 2015 that the legal obstacles blocking ZFS on Debian were cleared, the package is still not in Debian. The package is again in the NEW queue. Several uploads have been rejected so far because the debian/copyright file was incomplete or wrong, but there is no reason to give up. The current status can be seen on the team status page, and the source code is available on Alioth.
As I want ZFS to be included in next version of Debian to make sure my home server can function in the future using only official Debian packages, and the current blocker is to get the debian/copyright file accepted by the FTP masters in Debian, I decided a while back to try to help out the team. This was the background for my blog post about creating, updating and checking debian/copyright semi-automatically, and I used the techniques I explored there to try to find any errors in the copyright file. It is not very easy to check every one of the around 2000 files in the source package, but I hope we this time got it right. If you want to help out, check out the git source and try to find missing entries in the debian/copyright file.