I am sorry for criticising your otherwise excellent project, but I think you need this feedback.
I was resuming working on some OpenKIM related stuff after a brief hiatus. In the mean time, version 1.9.2 has been released, and I noticed that installation is now a completely standard configure - make - make install procedure. Great work!
Still, if I had not known how to proceed, I would have given up. After installing OpenKIM, I wanted to install some models. I remember from earlier that there is now a script that can maintain a collection of models. Armed with that knowledge, I began looking on the web page for documentation reminding me how to use it. Soon, that turned into a search for any kind of information about how to install models. I found no mention of the script whatsoever. In the contrary, I found many places stating that you should install models from source, with links to the database of source code but no hint as to how to “install from source”. In the end, I looked for the script in the installation folder (I knew it had to be there) and fortunately it gives a decent help text when called without arguments.
I am afraid this is the greatest “threat” to the OpenKIM project. It will never take off if people cannot find out how to use it - either because that information is not on the web pages, or because new users cannot find (or understand) the information.
I suggest that you write a simple OpenKIM Getting Started guide - one that does not try to take all possibilities into account, but just handles the simplest cases. I will add such a guide myself to the Asap documentation (which certainly suffers from the same problems, by the way - this is difficult to do right!)
With my best regards