It's been a long time, so maybe I'm misremembering things, but I seem to remember ARJ being the "cool" replacement for ZIP, but then when RAR came along, ARJ quickly died out.
Also I remember ARJ and PKZIP being used legitimately while I can't think of a single time I encountered a rar file in a non piracy context. Actually when I got my first job fixing up desktop computer in a large public institution the presence of winrar was a sure sign that I was better off airgaping the computer immediately, scanning with an offline antivirus and backing up noninfected user data and then reinstall, hoping I would not encounter child porn.
Eeeeeh I spent two decades pirating stuff ending with being a co-admin for one of the largest warez sites in Central Europe and I can tell you in all this we were clean. (Note this ended twenty years ago.) There was enough trouble with the law for just stealing software we didn't need the forces hunting for CP on us too.
