As explained in this answer software licenses that assert some form of copyright should include a year/author or they may not be recognized in the case of a future dispute.

Does the same thing apply to CC0? The CC0 FAQ recommends it, but doesn't require it and it isn't accompanied by a "Copyright ©" so it obviously isn't the same thing as in the answer linked above.

If it is required, does it have to be set in stone forever? So if I use my GitHub username and then change that username later (or change my contact e-mail) am I allowed to change it in the author note? Or does this void the license?


Since CC0 is essentially a way of waiving copyright, you don't need to add a "Copyright (C) ..." line. I generally replace that with a "written by Joe Blogs 201x" to allow subsequent users/distributors to keep track of the code's history but that is not required.


The copyright and the license are two different things.

Placing (c)2017 Joe Blogs in a document is stating that you own the copyright of the work and are claiming the rights related to the copyright. If you don't openly display your copyright ownership then you may later need to offer proof that you created and published the work in any dispute and may even be asked to provide a compelling explanation as to why you didn't openly claim copyright at the time of publication.

As the owner of a copyright you have the ability to license the work to others. This gives you the power to choose and enforce the terms the work is licensed under.

As for usernames, "Joe Blogs" is the legal copyright owner. Authors can use pen names and have those names displayed in copyright notices so the same should apply to online usernames. Using an online name for copyright purposes could require further proof that you used that name at the time of publishing the work, which would need to include the old and new usernames to prove that both usernames were used by you.

While formal copyright registration has been voluntary for some time, it can be useful for some works such as art or photos to help prove ownership at a later time. For most works it is common practice to display (c)2017 Joe Blogs as a claim of copyright.

  • 3
    Well-written informative answer, but doesn't actually answer the question.
    – Wingblade
    Dec 11 '17 at 13:21
  • 1
    While this answer discusses copyright notices, how does this explain their relation to CC0 dedications?
    – amon
    Dec 11 '17 at 14:06
  • I would say adding (c) is always recommended but not required. By placing (c) in the file you are openly claiming the rights related to the copyright of the work, which includes the right to enforce licensing terms. That is the only relationship between the copyright and license. While cc0 is public domain, the copyright owner is still the only one with the ability to make the work freely available, by adding (c) you are claiming you have that ability.
    – sambler
    Dec 14 '17 at 17:22

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