Creative Commons (CC) is a non-profit organization founded in 2001 by Lawrence Lessig, Hal Abelson, and Eric Eldred. The concept of CC emerged as a response to the restrictive copyright laws that make it difficult for artists, scientists, and educators to share their work with others and foster collaboration.
Unfortunately, the Creative Commons organization requires unnecessarily complicated attributions. This will discourage many potential users. An Australian university even offers an attribution builder:
“Pink elephant” by conceptphoto.info is licensed under CC BY 2.0