http://chronicle.com/img/subscribe-footer.pngBy Rebecca Koenig. When the orange Chegg bus rolls onto a campus, one person is unlikely to be excited about its free swag and energy drinks: the college-bookstore manager. The rise of online textbook retailers such as Chegg, Amazon, and Half.com, has put official college and university bookstores on the defensive. Once the default source of course materials, campus bookstores run by Barnes & Noble and Follett are responding to the pressure by cracking down on competitors’ on-campus advertising, which bookstores contend violates their exclusivity contracts with colleges. Read more...