Creative Commons licenses are built on traditional copyright. They may be free, but they are proper legal documents and are enforced using the same proceedures as traditional copyright law. They are simply a way to allow creators to easily communicate which rights they reserve, and which rights they waive for the benefit of other creators.

There are some basic clauses that enable this:

Attribution Attribution. You let others copy, distribute, display, and perform your copyrighted work — and derivative works based upon it — but only if they give credit the way you request.

Noncommercial Noncommercial. You let others copy, distribute, display, and perform your work — and derivative works based upon it — but for noncommercial purposes only.

No Derivative Works No Derivative Works. You let others copy, distribute, display, and perform only verbatim copies of your work, not derivative works based upon it.

Share Alike Share Alike. You allow others to distribute derivative works only under a license identical to the license that governs your work.

Interestingly, when these licenses are applied to online works, they contain meta-data that describes them and allows the works to easily be found online. This is why the CC search functionality built into Firefox is so useful - it helps  people easily find works (e.g. pictures) to re-use legally.This can enhance the pass-along (aka viral) effect of some creative works.

Lastly, the fact that these licenses are free should not be overlooked. Hiring a lawyer to license a work appropriately can be expensive and complicated. When you apply a CC license to your work, you're bringing to bear some of the most outstanding legal minds in the world today. These licenses were designed to work in today's hyperconnected world.
Posted
AuthorDave Duarte