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Scroll down to Usage Rights and select Creative Commons
To promote creativity, innovation, and the spread of knowledge. ~U.S. Constitution
The right to use copyrighted materials freely without payment or permission for purposes such as, "criticism, comment, news reporting, scholarship, and research. ~Doctrine of Fair use
When a user of copyrighted materials, adds value to, or repurposes materials for a different use from that for which it was originally intended, it will likely be considered transformative use; it will also likely be considered fair use. Fair use embraces the modifying of existing media content, placing it in new context. ~Joyce Valenza
The Transformative Factor - Purpose and Character of Use ~ Copying and using selected parts of copyrighted works for specific educational purposes qualifies as fair use, especially if the copies are made spontaneously, are used temporarily, and are not part of an compilation. At issue is whether the material has been used to help create something new, or merely copied verbatim into another work.
Nature of the Copyrighted Work: For copying paragraphs from a copyrighted source, fair use easily applies. For copying a chapter, fair use may be questionable. There is more leeway to copy from factual works such as biographies than from from fictional works, such as plays or novels.
Amount and Substantiality of Portion Taken: Duplicating excerpts that are short in relation to the entire copyrighted work or segments that do not reflect the "essence" of the work is usually considered fair use.
The Effect of Use on the Market: If there will be no reduction in sales because of copying or distribution, the fair use exemption is likely to apply. This is the most important of the four tests for fair use.
An alternative to Copyright.... if you create something you can give it a CC license to make it much less restrictive.
The Licenses... http://creativecommons.org/about/licenses/meet-the-licenses