Ratemyprofessors.com gets it

Most students are familiar with ratemyprofessors.com as it is a resource for deciding which section of a class you should take based on student reviews of professors. If you can get past the gimmicky and somewhat unprofessional chili peppers and angry student reviews, there is real value there. The site has made an intelligent manuever by creating a facebook app for its rankings. This is a good example of working with the existing Web 2.0 framework to advance your value proposition.