Is there a way to hide the content of my wiki site? I want to allow users with an account to view the content after login. Is this possible under Mediawiki?
Yes, of course it's possible! That's why MediaWiki has users and groups!
http://www.mediawiki.org/wiki/Manual:User_rights
http://www.mediawiki.org/wiki/Manual:Security
http://www.mediawiki.org/wiki/Manual:Preventing_access