“The Web Time Forgot” in today’s NY Times describes the work on hyperlinking and searching documents in the early 20th century – ancient history for things digital. The article highlights the work of Paul Otlet, and makes the case for the importance of the hyperlink. The article links to other background material and primary sources. See Boyd Rayward’s 1975 biography of Otlet, available in pdf format.
Before actual computers, before actual networks, and certainly before the web, Otlet understood that texts can be linked together by embedding an address of a related document in another. The physical instantiation of reaching one text from another is not the conceptual breakthrough. It’s the simply the idea of embedding instructions for accessing one text in another.