What about hypertext?
Ideas about hypertext are relatively old, especially considering the development of computer science in general. What happened to hypertext and the initial concept of it? When discussing hypertexts today, their importance is exceptionally to our quotidian life, especially when considering their most frequent occurrence, markup languages. Do they satisfy the intial concept and where is the development heading towards?
The initial idea of hypertext or links is based on Vannevar Bush's vision in 1945 of the Memex (memory extender) and its trails, where documents and sources are linked through a persistent address. His vision was revolutionary, because it catered inspiration for new ideas of scientists for many years to come. His motivation was the heavily expanding knowledge swelling from the manifold research areas. The Individual is confronted with many results and conclusions and has problems to memorize them. According to Bush specialization of the individual is inevitable for the progress, but with it comes the difficulty of interdisciplinary understanding. This hindrance could not be adequately succumbed in traditional ways of instruction or information delivery. Therefore, a machine to display, link and visualize these links is necessary to serve and search information.
This vision is certainly prodigious, since computers in this time where mainly used for calculation, in particular for the ballistic calculation or scientific research. They were by no means all-purpose machines, nor accessible or operable by an individual. During the sixties and the beginning years of the seventies, Theodor H. Nelson addressed the Bush vision from As We May Think  and expanded them to his new concept of hypertext, which is the mentioned the first time. Namely the paper As We Will Think , his Project Xanadu  and his book Computer Lib/ Dream Machines  promoted, advanced and concretized to some extent Bush's description. Nelson is not from the applied or natural sciences, but a studied philosopher. His primary intention was to make movies, like his father. This is why he thought the computer to be a medium for the realization of his foresight, the hypertext or a medium, which can neglect the constraints of paper. In addition, computer screens resemble Television or projection screens a lot.
His approach is a generalized form of Bush's trails and best expressed as a textual structure, which cannot be conventionally printed. It serves to spread information among professionals or laymen in a decentralized network in multiple bidirectional associative links. The human mind is his model, since humans think associative as they have memories connected in various ways. Furthermore, the sequential and bounded nature of texts on paper is a thorn in his eyes. Subsequently, his conceptualization of hypertext drafts abstractly a personal multi-purpose computer, which delivers information independent from its content in a parallel and easily humanly accessible manner.
Interestingly, shortly after his brainchild, machines, which we could call personal computers and graphical user interfaces (GUI) emerged. Some implementations were realized with Nelson, but all were inspired by his approach. The paradigms of windows and electronic mail were inspired by his ideas. The standard keyboard, direct symbol manipulation, digital libraries and information networks are only some of the concepts he worked on with colleagues like Douglas Engelbart, namely the inventor of the computer mouse. Many other forms of hypertext stem from this approach, such as SGML (Standard Generalized Markup Language), WWW (World Wide Web), HTML (Hypertext Markup Language), XML (Extensible Markup Language) or WIKI. But all of them only satisfy his approach to some degree. He expresses his discontentment about the evolution of the implementations of his creation in many publications or on his YouTube Channel .
Nelson's proper implementation, Project Xanadu, just like the Memex was and is never fully realized to the present day. Since he himself is a “media guy”, he is reliant on techies to materialize his ideas into machine-code in any way. Fortunately, his more than fifty years old project is realized in some prototypes and is still under development (browser-demo). His stubbornness on the original implementation of and obsession with his thoughts may have let him been overtaken by the improvements of modern technology. The modern realization of the internet and other computer technologies surly points towards the right direction. For example, the latest web-technologies as HTML5, XML and CSS strongly rely on the separation of content and representation. On the other hand, it is necessary to have a visionary to push development with his extreme, but still abstract and interpretable objectives.
 Project Xanadu