> ReiserFS was never hugely popular or anything

ReiserFS was the default filesystem on some distros for a period of time -- 6 years for SUSE. It was incredibly popular for systems that had lots of small files due to its tail packing feature (maildir, Gentoo Portage, working with projects that had a huge tree of source code)

Reiser4 was incredible too and just as it was starting to gain traction Hans murdered his wife. A real shame, a lot of the work Namesys did was novel and quite impressive.