What is the name of your state (only U.S. law)? Florida
I am a joint copyright owner of some digital content that I am planning on releasing under creative commons.
Do I need to put any kind of attribution in the content about the other party who holds joint copyright as well?
You will need to credit the original author(s).
As a joint author, and absent any agreement to the contrary, you can issue non-exclusive
licenses to others, allowing third parties to use the joint work. If any profits are generated, you must share these profits with the joint author(s) and the joint author(s) must share with you any profits they generate from the work.
Although you are considered owner of the rights (albeit a co-owner) and as such you are generally free to do with the copyrighted work what you want, you cannot "destroy" the copyrights in a joint-authored work by signing away any exclusive
rights in the co-authored work, without the express written consent of the other author(s). You can
, however, transfer all of your exclusive rights in the work (your joint ownership of the work) to another.
As an important note, a lot of authors of joint-authored works wind up in the courts with disputes over the copyrights. If you and your co-author(s) are not currently operating under a written agreement, it would be smart to sit down with an IP attorney prior to going your own ways with thoughts of sales or distribution of the work you created together. A written agreement can define and clarify the rights and responsibilities of the joint owners and can define and clarify the copyrights each co-author holds in the work. A written agreement can help the joint owners of the copyrights in the work avoid a legal dispute that entangles them in a costly lawsuit.