Markets In Everything: Exam Advertisements

From CNN:

In tests for teacher Tom Farber's high school class, students can demonstrate their mastery of calculus and find out where to get braces or even a haircut.

Squeezed by classroom budget cuts, the Rancho Bernardo High School teacher is selling ads on his exams to cover the costs of printing them.

"It raises money for the teachers and it's amusing for the kids, so it seems like a win-win," said Luke Shaw, 18, a student at the suburban San Diego, California, school.

What will this do to the supply of exams? Since it takes time to grade both homework and tests, my thinking is that teachers would have an incentive to substitute away from homework and towards tests. Similarly, how will the content of the test change, and what kind of advertisers will be attracted to this venue? The Superbowl ads draws advertisers for more social or group oriented goods. Will exam ads draw more stress relief oriented advertisers? Will they tend to be Sylvan-like tutoring services? How will advertisers differ between subjects, say English and Math?