Here is a Forum about selective mutism that I administer. Japanese only, though.
http://atbb.jp/smjournal/index.php
There are many BBSes and Forums about selective mutism in Japan. Administrators are individuals. Some of them are people who suffered (suffer) selective mutism. Some of them are mothers of children with selective mutism.
Many Japanese websites about selective mutism are administered by individuals. So are Japanese BBSes and Forums.
But I think that the largest BBS or Forum about selective mutism is a thread of 2ch.
http://life8.2ch.net/test/read.cgi/utu/1183563051/l50
2ch is the largest Internet forum in Japan. One of the characteristics of 2ch is that people can post their comments anonymously. I guess that's one of the reason why 2ch is so large.
Index of SM in Japan
