hypertext

Hypertext is a non-linear medium for presenting information in which text or other media units contain references, or hyperlinks, to other documents or data. By clicking a link, a reader can navigate to related content without following a fixed sequence. Hypertext is a foundational concept of hypermedia and the World Wide Web, and the term describes systems where content is interlinked rather than read linearly.

Origins and development: The idea of linking related information dates to Vannevar Bush's 1945 Memex, which imagined trails through connected materials. In the 1960s–70s, Ted Nelson popularized the term hypertext and pursued Xanadu, a bidirectional linking system. Early demonstrations appeared in Doug Engelbart's work. The World Wide Web, created by Tim Berners-Lee in 1989–1990, popularized hypertext with HTML hyperlinks and URIs.

Technical aspects: Hypertext links reference targets identified by URLs or URIs. In HTML, hyperlinks are created with anchor elements. Links may point to whole documents or to specific sections, and can be unidirectional or bidirectional. Hypertext is often part of a hypermedia system that may embed images, audio, video, or interactive content. Navigation follows a graph of interconnected nodes rather than a single path.

Impact and terminology: Hypertext enabled rapid information discovery and the growth of the Web as a vast network of linked documents. In common usage, hypertext refers to text with links, while hypermedia extends the idea to other media. Challenges include link rot, accessibility considerations, and preserving context and provenance as content evolves.