The Center for Social Media at American University released in 2008 the Code of Best Practices in Fair Use for Online Video (html, pdf). The document describes six practices that fall under fair use. While the document is primarily aimed at video creators, many of the principles and limitations are worthwhile reading for educators. The six highlighted practices are:

1. commenting on or critiquing of copyrighted material
2. using copyrighted material for illustration or example
3. capturing copyrighted material incidentally or accidentally
4. reproducing, reposting, or quoting in order to memorialize, preserve, or rescue an experience, an event, or a cultural phenomenon
5. copying, reposting, and recirculating a work or part of a work for purposes of launching a discussion
6. quoting in order to recombine elements to make a new work that depends for its meaning on (often unlikely) relationships between the elements