Here is their sign-up page http://www.scholarpedia.org/wiki/index.php?title=Special:Userlogin& create=yes
Notice the requirement to be "affiliated" with some institution. So again the entire concept of Scholarpedia is limited to universities and possibly a few research laboratories.
I believe the concept of WikiJournal would be universal, just like Wikipedia. Anyone can be an expert on any topic. The validity of your expertise is not measured by your affiliation, but rather by your articles.
Will