"Hypertext" is a scary newfangled word, credited to a visionary named Ted Nelson who still dreams of a world in which all information is hyperlinked. For a good survey of the theoretical and practical possibilities of the notion, see George Landow, Hypertext: The Convergence of Contemporary Critical Theory and Technology (Baltimore: Johns Hopkins, 1992). But bear in mind that you've been doing hypertexting all your life: the very idea of a "footnote" is that you leap out of your linear text to another kind of discourse, then return when you are done. The WWW browser you are using to read this paragraph is merely automating the process. For an example of the traditional footnote automated by the WWW, click here to go to a recent paper of my own, cursor down to highlight one or another of the footnote calls, and click on that, then trace your way back here when you've read enough. (The history of non- linear reading is more or less co-extensive with that of the codex book, but we still like to imagine ourselves in a hammock with Jane Austen, reading sequentially till the cows come home.)
But one aspect of the networked hyperlink is important to note: not only can links go both ways, but the link itself can take you to far more abundant and substantive material than the point of origin -- the footnote can be much longer than the thing footnoted. This screen you are reading, if you pursue both the references to my own papers that you could click on easily here, exemplifies that exactly! You could click off into hyperspace and never come back! This is disconcerting; it will surely change the way we read and think.