Many authors of online resources are adapting to the new way we use and reuse material on the Internet by turning to Creative Commons licenses. You've probably seen the logos for Creative Commons licenses on various scholarly and popular websites:
This license has a lot of the most common elements of CC icons. For a description of what BY, NC, and SA mean, and how you can use CC licenses in your work, see the Creative Commons About page.
What is Fair Use?
Fair Use is the allowance of limited use of copyrighted material without permissions, and is based on U.S. copyright law. It is primarily practiced in educational and non-profit settings, including libraries, the documentary industry, universities, and research centers.
Section 107 [of the U.S. Code] contains a list of the various purposes for which the reproduction of a particular work may be considered fair, such as criticism, comment, news reporting, teaching, scholarship, and research. Section 107 also sets out four factors to be considered in determining whether or not a particular use is fair:
The purpose and character of the use, including whether such use is of commercial nature or is for nonprofit educational purposes.
The nature of the copyrighted work.
The amount and substantiality of the portion used in relation to the copyrighted work as a whole.
The effect of the use upon the potential market for, or value of, the copyrighted work.