Materials in the public domain may be copied, altered, and otherwise used freely. These materials do not have copyright because their copyright either was waived or forfeited, has expired, or was not applicable. For example, works created by the United States government are in the public domain in the United States as they are excluded from copyright. Works by authors like Mark Twain and Jane Austen are in the public domain because the authors died over 100 years ago, and their works' copyright has expired.
For more information, consult:
Insert link to copyright guide here
According to creativecommons.org, "Every [Creative Commons] license helps creators -- we call the licensors if they use our tools -- retain copyright while allowing others to copy, distribute, and make some uses of their work -- at least non-commercially. Every Creative Commons license also ensures licensors get the credit for their work they deserve. Every Creative Commons license works around the world and lasts as long as applicable copyright lasts (because they are built on copyright)."
There are different use allowances with the different types of Creative Commons, or CC, licenses:
By foter - http://foter.com/blog/how-to-attribute-creative-commons-photos/ (image was available: Foter.com infographic CC.jpg (JPG). Archived from the original on 14 February 2017.), CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=73846519
Fair use provides the broadest and most flexible exception to copyright limitations. It is technology-and-format-neutral and can be applied to any medium. A fair use determination requires a good faith analysis of four equally-weighted factors specified in the law. Fair use can be the most challenging and difficult determination to make. The following tools can help you understand the four factors, weigh them, and make an informed decision.
Whether something can be considered a fair use exception depends on four factors:
1. Purpose and character of the use and whether it is for commercial or educational/non-profit purposes
2. The nature of the copyrighted work (creative and imaginative versus factual)
3. Amount and substantiality of portion use
4. Effect of the potential market for or value of the work
The more factors that apply, the more likely something might be considered fair use.
