For further reading (optional):
Note that "[o]wnership of a copyright … is distinct from ownership of any material object in which the work is embodied. Transfer of ownership of any material object, including the copy or phonorecord in which the work is first fixed, does not of itself convey any rights in the copyrighted work embodied in the object." 17 U.S.C. § 202. That means when you buy a book, you own the physical object, and the right to re-sell that object, but not the copyright or the right to reproduce the book's text. Most books come with language like "All rights reserved."
Much software claims to be licensed, not sold, with the terms of an End User License Agreement ("EULA") dictating what you can and can't do with the product. One can hardly venture online without encountering (claimed) contracts. ISPs condition connection to
the Internet on acceptance of “terms of service”; websites offer up terms of
use; digital purchases carry shrink-wrap or click-wrap licenses. Contractual private ordering allows parties
to customize the legal rules of their interactions when the defaults don’t suit.
Others choose to license their copyrights very differently, using it to create entirely new ways of doing business.
The GNU General Public License (GPL) is a copyright license that uses copyright
to enforce not closure but openness. The GPL encourages users to modify software
and redistribute it – provided they do so on the same terms: with the
source code to enable their users to do the same. Read the text
of the GPL and watch how it accomplishes these “copyleft” attributes.
Since the GPL’s introduction in 1984, a whole ecosystem of “Free Software” and open source development has emerged. As the Free Software Foundation puts it, “you should think of ‘free’ as in ‘free speech,’ not as in ‘free beer.’” The GPL-licensed Linux kernel and GNU software power everything from embedded devices to TiVo digital video recorders (see <http://www.tivo.com/linux/linux.asp>) to Google. Companies such as RedHat sell packaging and services around Free Software.
The GPL has rarely been litigated because most companies confronted with evidence of violations have preferred to settle. See, e.g., Aaron Weiss, “The Open Source WRT54G Story,” Wi-Fi Planet, <http://www.wi-fiplanet.com/tutorials/article.php/3562391>. It is often said that most of the Internet runs on Free and open source software ("open source" is the name used by the more pragmatically oriented branch of the movement). Read the GPL to see how this works legally, then read the Cathedral and The Bazaar to see the kind of social structures that support Free and open source software.
Creative Commons has more recently turned the open-source spirit to non-software copyrights. Look again at the Creative Commons model in the “Commons Deed” and “Legal Code” to the Attribution-ShareAlike license -- options for authors and artists to publish with “some rights reserved.” Creative Commons licensing is made available as an option in many blogging packages and photo sites such as Flickr, and licenses have been "ported" to 44 different jurisdictions. Sites such as Jamendo and Magnatune have built businesses around CC-licensed music.
How do Free and open-source software and Creative Commons licensing fit into broader copyright law and business? CC+ aims to offer some options.