Creative Commons
It is a nonprofit organization that enables the sharing and use of creativity and knowledge through free legal tools.
They have a free and easy-to-use copyright licenses. But this is not an alternative to copyright. It only enable you to modify your copyright terms to best suit your needs. This licenses provide a standardized way to give the public permission to share and use your creastive work on conditions you choose.
So for example, if you want to let people share and use your photographs, but not allow companies to sell them, you should consider publishing it under a Creative Commons license. It gives you flexibility and protects the people who use your work. But not only individual creators, also large companies and institutions use this creative commons tools to keep their copyright.
It`s a good thing!!