Copyright laws apply to all materials found on the Internet just as they do for other traditional materials (textbooks, magazines, etc.). The instance a web document is placed on the Internet, its content and images are copyrighted. Absence of a copyright notice does NOT mean that the document is not copyrighted. Particularly because web documents are available to the entire world, unless you place them in a password protected directory, you need to be careful in your own web materials that you are not using someone else's materials without their permission.
Just because you own something does not necessarily give you the copyright or privilege of placing it on your web site. For instance, if you purchase a photograph and want to scan it and place it on your web page, you must first have permission from the copyright holder (normally the photographer). The same is true for musical CDs -- just because you purchase it, you do not have the right to put a song from that CD on your web site. Only the copyright holder can give permission to use it on the World Wide Web.
Word of Caution: Do NOT use images of Disney characters or other popular cartoon images, like Dilbert, Calvin & Hobbs, Peanuts characters, etc. These images are copyrighted, and you open yourself and the University to a lawsuit. Other taboo images are: the UA mountain/saguaro logo licensed for use by the Athletic Department only; or company trademarks/logos.
The UA Copyright Librarian has commented in presentations about copyright that people ask her if it "okay" to use this or that item on a web page. There are not simple "yes" and "no" answers in most situations. If you want to use published materials in your web site, follow the same types of rules as if you were writing a traditional paper. You cannot extract a substantial portion of someone else's work without crediting them and without getting permission. The same is true about images or photographs you find on the web. Being on the web does not make something "public domain".
The safe and prudent policy to follow is, if you want to use someone else's textual material or images (whether they are on the web or not), you should check with the copyright holder of the material or the webmaster at a particular site. If you get permission to use materials, keep a copy of the documentation giving you permission.
Protecting your own materials
Although it is not required to have a copyright statement on your own materials you create for the web, if you want to make it clear that you do not want your materials, images, photographs, etc. used by others without them asking, add a copyright statement to your main page.
For anything created through your job with the University of Arizona, this statement could be used: © 2003 The Arizona Board of Regents. All contents copyrighted. All rights reserved. It is not necessary to have this statement on all your pages. Putting it on your main page is sufficient, as long as your other documents link back to this main page.
Now, will just adding this statement "stop" someone from stealing your material? Obviously, no. And it is doubtful that you nor the University have the resources and time to track down violators. But having this statement is better than not having any statement at all.
Reversely, if you create original materials, images, spreadsheets, that you want to be used by anyone without restriction, indicate that on your main web page or where it seems appropriate. You can also put restrictions such as this: These items (or whatever) can be used by any person for educational and non-profit use.
Using page designs from other sites
Currently, this is a VERY gray area as far as copyright laws are concerned. It gets extremely complicated. This issue has not been totally decided but ethically, you should not steal another's web page design. This is particularly true if the site has a unique look and layout, with graphic elements that are part of its look.
To read more on the complicated issue of copying other web page designs, refer to The Copyright Website's at www.benedict.com/. This site keeps current on all the Internet copyright issues so you can keep current without taking hours of researching time to find the information you need.
Linking to a web site
A URL is a fact, not that much different than a street address. While it is unique, it is not copyrightable. However, it is considered good netiquette to contact the site that you wish to link to and ask for permission to establish a hyperlink to their site BEFORE you do it. However, a list of URLs that a web author has compiled in a unique way is copyrightable. So, if you come across someone's Neat Links to various URLs, DO NOT copy the entire document for use on your web site. You will be in violation of copyright laws.
Using copyrighted materials on a class site
Although the general "rule" is to not use copyrighted materials on a web site without permission from the owner, people putting up an instructional web site are allowed to use copyrighted materials IF the web site is password-protected, so that only persons taking the class can view the copyrighted materials. This is similar to putting materials in reserve in a library, for use by students or class members.
You should still clearly show where these materials come from. For details about creating a password protected directory, see cals.arizona.edu/ecat/web/password-protect.html.