When enabled, GlobalCssJs adds a "Shared CSS/JavaScript for all wikis" entry to the Appearance tab on Special:Preferences, right below "Shared CSS/JavaScript for all skins:". The links to the user's personal global.css and global.js pages are not generated at all if and when $wgConf isn't defined -- and that's the case for many non-Wikimedia wiki farms.

We need at least some kind of a configurable override to allow specifying the base URL in GlobalCssJsHooks::makeCentralLink. For ShoutWiki, I literally commented out the original WikiMap code and replaced it with this filthy hack:

			return '<a class="external" href="http://www.shoutwiki.com/wiki/' .
				htmlspecialchars( $title->getPrefixedText(), ENT_QUOTES ) .
				'">' . htmlspecialchars( $message, ENT_QUOTES ) . '</a>';

Needless to say that this isn't exactly a scalable solution and it makes upgrading the extension harder, too.