My first reason was an unwillingness to learn those systems. I did take a look at Joomla and CMSimple however. Unfortunately, they didn't allow clean URLs. N

My first reason was an unwillingness to learn those systems. I did take a look at Joomla and CMSimple however. Unfortunately, they didn't allow clean URLs. Now, the genuine advantages of USSM over nanoc and Jekyll may be simplicity, the navigation menu, and extensibility. Regarding simplicity, the manual is very short, and almost complete. I even describe some of USSM's inner workings. I believe you don't need more than 1 hour to understand everything besides the source code itself. The navigation menu, I don't know. The few sites I saw that used Jekyll didn't show such a thing, so I assumed it didn't do that. I didn't know about nanoc at the time (seeing the tutorial, I assume it does provide a similar menu). USSM's extensibility isn't tied to any programming language besides the shell. This is because I wrote several command-line utilities that do much of the work. As a result, a new module can fit in a few lines of Bash (see the source code for ussm-core.sh and ussm-title.sh).