I had suggested before also that questions from new users should not be posted directly on the site rather they should be moderated first and they should be visible to only users with high reputation (say 600 rep) so that duplicate posts, rants and spam like posts could be controlled. And once the user has atleast 10 reputation or he/she has asked two questions which are not a duplicate and are not a spam, this moderation for posting his/her questions on site should be removed.

This would make Ask Ubuntu clean.