quite a while ago I added links to the new wiki.
Today I revisited the old wiki and had to remove a SPAM post on the main page. It seems a registered user has added this. As the old wiki is not updated anymore I suggest to lock down or replace it with a redirect using .htaccess and mod_rewrite.
example .htaccess file placed in /srv/www/…/htdocs/forge/
RewriteRule ^(.*)$ http://www.seeedstudio.com/wiki [L,R=301]
mod_rewrite must be loaded and activated in the apache2 configuration of course. The status 301 (permanently moved) should also remove search engine hits and thus it showing up in their indexes in a while.