One of the most substantial challenges when working with digital media is the effort required in preserving it and documenting its existence. Hard drives fail, DVDs crack, and servers are taken down. Anticipating and mitigating these inevitable failures has helped cement a culture of redundancy in our private information technology infrastructure, but what of the commons? Projects and features like Archive.org’s Way Back Machine, Google’s Cache, and Wikipedia’s history, all provide glimpses of what once was on the Internet, but what happens when you need to verify that a work was released under Creative Commons?

In this vain, Scott Carpenter ruminates on the issues invoked when a popular Flickr photographer switches his work back from attribution to All Rights Reserved:

I had saved a handful of his photos to my hard drive, and checking another one, it also had been “taken back.” I left a comment on the one photo, pointing out this change in licensing. Terry’s work receives lots of comments on Flickr and this picture was posted almost a year and a half ago, so I didn’t expect much in the way of a response, but he sent me an email thanking me for my comment and saying, “Yes I had to change the rights as I started finding my photography being used without my permission for advertising and other professional media.”

As you may or may not know, CC licenses are irrevocable, but this doesn’t mean creators can’t cease offering a work under the license. When a licensor changes the license of a work (whether it is Creative Commons or otherwise) it simply means that whomever comes across the work in the future will be bound by the new terms and not the older ones. It does not mean, however, that the older licenses are invalidated. For more information about this read our FAQ.

As for the question of verifying whether a work was ever released under a CC license, the innovative ImageStamper.com can provide this exact service for flickr photos. We used ImageStamper to time stamp all 157 photos used in Jesse Dylan’s ‘A Shared Culture‘ so that we would have proof, going forward, that a particular work was released under a given license. WebCitation.org‘s archive feature provides essentially the same functionality for any given webpage and also provides a permanent URL for the snapshot.

Ultimately, this is the exact question we were interested in answering by creating the Creative Commons Network. Instead of providing proof of others choice to use a CC license, you can use the Creative Commons Network to show the world that both Creative Commons and you have verified that you’ve released a work under CC.