The <site> field is the Internet domain name of a system that holds the information. Following the site is a file name (in the syntax of that machine), and finally there may be an anchor, which is a location within the file.
As an example, here is the URL for the NCSA home page document:
http://www.ncsa.uiuc.edu/SDG/Software/Mosaic/NCSAMosaicHome.htmlWhen you start Mosaic it uses this URL to connect to the http server at NCSA (the machine named www.ncsa.uiuc.edu) and retrieve the current version of the home page, which is in the file named /SDG/Software/Mosaic/NCSAMosaicHome.html.
The reason you need to know about URLs is that they allow you to access information directly without traversing a path from the home page. If you hear about an interesting new document, for example a hypertext presentation of an art exhibit, you can view it by using the Open... command in the File menu. When you activate this menu option you will see a prompt to type in a URL name; when you are done Mosaic will open the document by using the URL to find the document on the Internet.
Under the Navigate menu, there is an option called the Hotlist. This brings up a dialogue box in which users can add documents to their person Hotlist. Later, a user can jump straight to these documents without remembering the URL or how to get there through other links. Refer to the on-line documentation for more information about URLs.