Yes, and more importantly: there are still some fresh ideas coming out of it. The developers behind Gobo are operating systems and programming languages enthusiasts, so every now and then they use the distro as a platform for evaluating and sharing their ideas in a way that others can benefit from (and potentially improve upon).
This is a great comparison, written I believe by one of the Nix devs.
As far as Gobo is concerned, the outdated parts is that the /System/Links/{Executables,Libraries,...} has been replaced by /System/Index/{bin,lib,...} which makes it easier to build packages (less compatibility issues to deal with, since /usr is a symlink to /System/Index). So it's easier for a user to compile their own stuff and get it working.
And of course, the comment at the end about the project inactivity no longer applies: Gobo is alive and well. :)
Hi, GoboLinux dev here. While the projects do have somewhat different goals, I think the comparison is valid, since both of them modify the filesystem structure.
Both projects were started around the same time (2002). I _think_ we might have been ahead for a few months, but my memory may be failing me. I was shown Nix not long after Gobo was in the news for the first time (ah, the days of Slashdot and Kuro5hin... ;) )
I haven't looked closely at Nix for a long time, so things might have changed, but the main difference between Gobo and Nix, I think, is the degree of access you have to tweak the system by yourself.
Gobo keeps things directly user-tweakable (you can install your own programs with `./configure --prefix=/...; make; make install` if you want and Gobo will see it as a first-class citizen of the system), while Nix manages your filesystem tree on its own (it uses directories with hashes in its names, etc) so the user should only interact with packages via Nix's own tools. Of course, this is important so that Nix keeps its functional guarantees.
The goal in Gobo, on the other hand, is to give user full control (if you mess it up, it's your fault — but with a more organized filesystem, it's harder to mess it up).
I can't find a proper timeline regarding Nix(OS), but i get the impression that it existed purely as a package manager until very recently. At least over at Distrowatch they have Gobolinux history going back to 2003, while NixOS shows up only as recently as 2014.
[disclosure: I'm one of the guys developing it]