Mosaic provides a hypertext interface to the global Internet. Hypertext is text which contains highlighted links, called hyperlinks or anchors, to other texts. Each highlighted phrase (in color or underlined) is a hyperlink to another document or information resource somewhere on the Net. Single click with the left mouse button on any highlighted phrase to follow the link. To follow a link, in this sense, means that Mosaic will retrieve the document associated with the selected hyperlink and display it.
The Mosaic client communicates with HTTP servers. HTTP is the HyperText Transfer Protocol of the WWW (World Wide Web). Mosaic can also communicate with more traditional Internet protocols such as FTP, Gopher, WAIS, NNTP, etc. (Here is more information on these protocols.)
The hypertext documents viewed with Mosaic are written in HTML (HyperText Markup Language), which is a subset of SGML (Standard Generalized Markup Language). Among the many formatting features, HTML allows Mosaic to display inlined images. (In fact, an inlined images can serve as a hyperlink just like a word or phrase can). If you are viewing this documentation from within Mosaic, you are reading an HTML file being served off of an HTTP server located at the State University of New York at Stony Brook.
Mosaic also features unlimited multimedia capabilities. File types that Mosaic cannot handle internally, such as mpeg movies, sound files, Postscript documents, and JPEG images, are automatically sent to external viewers (or players). More details are available in later sections of the documentation.