In the US legal context:
Fair use allows the use of copyrighted material without permission from the copyright holder under certain circumstances. For libraries, educational institutions, and the public, the fair use doctrine is the most important limitation on the rights of the copyright owner—the “safety valve” of US copyright law.
Libraries may wish to consult the Association of Research Libraries’ ARL Fair Use Week promotional site to prepare events and encourage participation. The Fair Use Week Tumblr from 2014 is still a great resource, too! I like this tidbit from it:
The popular view of fair use is one sort of punk rock approach: take what you want until you get caught. Ask forgiveness, not permission. But that’s a mindset that assumes fair use isn’t really a right — it’s something you only get away with.
Look for more soon! From ARL:
Visit http://www.fairuseweek.org (site coming soon) or e-mail firstname.lastname@example.org for additional information. The website will be continually updated with information, a calendar of events, and links to blog posts, webcasts, activities, and resources.