Free licenses play a vitally important role in fostering creative and collaborative use of copyrighted material. Creative Commons is perhaps the best example, with a around 130 million works under CC licenses, which tell you in advance what you can and cannot do with a work.
Some have wondered how effectively you can enforce a free license if somebody violates the terms of it. Today the U.S. Court of Appeals for the Federal Circuit -- one of the most influential in the country -- answered that question forcefully by affirming the enforceability of free licenses through infringement claims. (We represented Creative Commons and several other organizations that support free and open source licensing as amicus parties in this case.)
This is a tremendously important victory for free licensing in a tremendously influential court. Read the full opinion here.