Teachers who deal with media think a lot about it. Parents of video producers and bloggers do too. So does everybody trying to understand the impact of the social Web on traditional media, including artists and the recording industry. What am I talking about? A part of copyright law that generates a lot of understandable confusion: "fair use." "Fair use is quite tricky because courts address it on a case by case basis after someone is sued. There is no list of what constitutes fair use," writes University of California, Berkeley, social-media researcher danah boyd. She's blogging about a just-released study, by media and legal scholars, that really advances the public discussion: "Recut, Reframe, Recycle: Quoting Copyrighted Material in User-Generated Video" at American University's Center for Social Media site. The study gives examples of "a wide variety of practices – satire, parody, negative and positive commentary, discussion-triggers, illustration, diaries, archiving and of course, pastiche or collage (remixes and mashups) – all of which could be legal in some circumstances," the Center says. Danah adds that the authors "try to assess which way the courts might fall, depending on practice. They also offer potential defenses that creators can make if they were sued in an attempt to build best-practices principles." This is valuable material for any family or classroom discussion or debate about fair use and intellectual property in the age of digital media and the participatory Web, when this discussion has never been more important (see "The age of remixes, mashups"). For an online debate on fair use, see the arguments of Columbia law professor Tim Wu and NBC Universal general counsel Rick Cotton in this New York Times blog. See also MIT professor Henry Jenkins's book, Convergence Culture (Henry's at HenryJenkins.org).