Copyright law grants creators with a set of rights over their works and the ability to transfer one or more of these rights to another party:
Publishers may present authors with restrictive agreements that call for their transfer of rights. As the copyright holder, the author should read the agreement carefully and consider the impact that the publisher's agreement would have on their copyright. Depending on the agreement, signing could prevent the author from distributing their work through an open access repository or personal website.
SPARC (the Scholarly Publishing and Academic Resources Coalition), a global organization "committed to making Open the default for research and education," emphasizes that: "Publishing agreements are negotiable. Publishers require only your permission to publish an article, not a wholesale transfer of copyright. Hold onto rights to make use of the work in ways that serve your needs and that promote education and research activities" (SPARC, "Author Rights"). An author addendum is a strategy to do so.
SPARC has created an amendment to publishing agreements that authors can use to retain rights to the works they have created. This document should accompany the original publishing agreement and authors should include a cover letter that points to the addition.
Other institutions have created their unique own addenda that in some cases offer more control over copyright. A list of the addenda available for use, created by MIT, the Ohio State system and others is linked below.
Copyright law allows an author or creator to restrict usage, distribution, or the reproduction of their works, but there is an initiative in place to help individuals who are interested in being less restrictive with their copyright: Creative Commons (CC) licenses. As the Creative Commons organization explains, "CC licenses are copyright licenses, and depend on the existence of copyright to work. CC licenses are legal tools that creators and other rights holders can use to offer certain usage rights to the public, while reserving other rights. Those who want to make their work available to the public for limited kinds of uses while preserving their copyright may want to consider using CC licenses."
Creators can choose to publish their work with one of six main CC licenses that offer varying degrees of restrictiveness. The following descriptions come from the CC website and more information can be found by clicking on the license image.
"This license lets others distribute, remix, tweak, and build upon your work, even commercially, as long as they credit you for the original creation. This is the most accommodating of licenses offered. Recommended for maximum dissemination and use of licensed materials."
"This license lets others remix, tweak, and build upon your work even for commercial purposes, as long as they credit you and license their new creations under the identical terms. This license is often compared to “copyleft” free and open source software licenses. All new works based on yours will carry the same license, so any derivatives will also allow commercial use. This is the license used by Wikipedia, and is recommended for materials that would benefit from incorporating content from Wikipedia and similarly licensed projects."
"This license allows for redistribution, commercial and non-commercial, as long as it is passed along unchanged and in whole, with credit to you."
"This license lets others remix, tweak, and build upon your work non-commercially, and although their new works must also acknowledge you and be non-commercial, they don’t have to license their derivative works on the same terms."
"This license lets others remix, tweak, and build upon your work non-commercially, as long as they credit you and license their new creations under the identical terms."
"This license is the most restrictive of [the] six main licenses, only allowing others to download your works and share them with others as long as they credit you, but they can’t change them in any way or use them commercially."