We often see new users make offtopic, low quality posts, with broken English and cries for help. Their posts look significantly different than most post on SO.
When I worked in publishing, we would frequently receive documents that were incorrectly formatted. This was a major problem and we wasted a lot of time sending emails back and forth.
It is slightly unconventional but, would showing new users a quiz where they have to identify good and bad posts help solve the problem?