Noted IP expert and Advisor in Chief to deviantART, Joshua Wattles, clearly defines Creative Commons for us:
You use a Creative Commons License for only one reason: to provide the broadest possible distribution of the work – for free – holding back only as much as you need for your own comfort zone.
Creative Commons Licenses have a reputation for simplicity and ease of use. They are readily available and they are free. They also seem familiar, at least on the Web. So it is easy to forget a basic fact: that they are use licenses and not devices to provide heightened protection for your photographs.
The United States copyright laws and those of most other countries start on the premise that the author/photographer obtains a monopoly over essentially all uses of a given photograph the author has made. It is absolute. Without any other agreement in place, there is no greater protection and no greater bundle of rights to be had by a photographer in his or her work than at the moment where the shutter goes off and the image is recorded whether on card or on film.
For the website, typically the author grants it the non-exclusive right to display the work, store the work and transmit the work all as part of the website – sometimes forever and sometimes only for as long as the author doesn’t delete the work from the website. The website also gets the right to change and alter the image as part of its display and sometimes to use the image should the website itself be publicized. There is also usually an acknowledgement of the way in which websites and the Internet work in terms of the ability to store the image and the lack of inherent security for the image once placed on the Internet.
But in this website example, all other rights of sale, of making any commercial use, of copying, of displaying the work elsewhere, of making derivative works – all of those rights are retained by the author.
Creative Commons Licenses work from a basic premise that the work is meant by the author to be made available for free to broad use by the general public. From this premise, the various versions of the Creative Common Licenses tweak the rights that the author is holding back from a broad grant that pretty much gives away everything else that the photographer got from the copyright law when the shutter went off. It is an upside down cake from typical commercial and non-commercial practice for licensing photographic images.
The various kinds of Creative Commons Licenses tweak on and off these factors: a duty to give attribution when used, the right to make derivative works, commercial uses, and whether a user must license other users in the same way in terms of open use and sharing. Consistent with the underlying premise of these licenses, there are no commercial terms in them with respect to royalty rates or any other compensation for use.
The bullet points for the Creative Commons Licenses are all simple, neat and clean. For example, they describe one version like this: “This license allows for redistribution, commercial and non-commercial, as long as it is passed along unchanged and in whole, with credit to you.” But when you click through to the actual license itself it will have language rivaling any top legal product in the market like this: “The rights granted under, and the subject matter referenced, in this License were drafted utilizing the terminology of the Berne Convention for the Protection of Literary and Artistic Works (as amended on September 28, 1979), the Rome Convention of 1961, the WIPO Copyright Treaty of 1996, the WIPO Performances and Phonograms Treaty of 1996 and the Universal Copyright Convention (as revised on July 24, 1971).”
Lions and Tigers and Bears. Oh my! All of this heavy text in service of broad distribution and open rights of use with respect to the work of the artist.
It is true that the scope and raw power of copyright protection is so broad that without a Creative Commons License it would be very hard to convince people on the Web that they could, in fact, use an image if that is what the copyright owner wants. This consumer/user problem is solved by the Creative Commons system of licensing. Creative Commons literally places the work into the commons for all see and use.
One final note: on both a legal level and on a practical level, it is essentially impossible to pull back a Creative Commons License from people who have relied on it. If a future client wants all rights exclusively, you will not be able to deliver if the image was previously licensed under a Creative Commons form.
Creative Commons License Selector: http://creativecommons.org/choose/
Short Explanations of the CC Licenses: http://creativecommons.org/licenses/
Example of an actual CC License: http://creativecommons.org/licenses/by-sa/3.0/legalcode