The internet consists of a vast network of computers connected by standard telephone lines and dedicated data lines. These telephone and data lines can be metal cables, fibre-optic cables, or microwave or satellite links. Computers are connected to these data lines by hardware devices called modems. The World Wide Web consists of a network of files stored on computers around the world called web sites. A web site is a series of interconnected 'pages' of data.
Web sites can contain text, still pictures, moving video and animation, and sound.
Consequently web sites can deliver information using a variety of delivery techniques, unlike traditional books, videos or audio tapes, which are by their nature more static and linear. For this reason, web sites, and CD-ROM programs that have the same features as web sites, are described as 'multimedia'. A significant aspect of multimedia programs is their ability to let the user navigate through the pages of data using 'hyperlinks'. Users can choose to follow items of interest, rather than be locked into a linear progression of information as in a book or video. Internet hyperlinks can allow users to navigate within the same web site, or from one web site to another, allowing the user great flexibility.