One of the reasons online resources cost so much is copyright (this is also why many books and articles are not available in full-text online).
Copyright is the legal means by which authors are able to profit from their work. The United States Constitution grants Congress the right to legislate laws regarding copyright.
Tthe United States Code of Law (Title 17) defines copyrighted material as "original works of authorship fixed in any tangible medium of expression, now known or later developed, from which they can be perceived reproduced, or otherwise communicated, either directly or with the aid of a machine or device."
Examples of copyrighted material include:
Web pages, software, email messages, and Internet audio and video files are also copyrightable.
For something to be copyrighted it is not necessary for the © symbol to be present. Copyright is assumed when the information is written or recorded in any manner. This means that even an unpublished manuscript is protected by copyright.
Copyright does not last forever. In general, a copyright is granted to the author and his or her heirs for the life of the author plus 70 years. (See the Copyright Duration Chart for exceptions.) Once the copyright has expired, the work is said to have entered the public domain. This means that the copyright owner no longer has exclusive rights to earn a profit from the sale of the work. Anyone who wishes to, may republish a work in the public domain without fear of infringing on someone else's copyright. This is why old classics, like Charles Dickens' Oliver Twist, can be found produced by many different publishers simultaneously.
Images used herein to illustarted copyrightable documents were obtained from IMSI's MasterClips and MasterPhotos Premium Image Collection, 1895 Francisco Blvd. East, San Rafael, CA 94901-5506, USA.