Hypertext is a system that allows non-sequential access to information. It was first introduced by Vannevar Bush in 1945 as "memex", which used microfilm and eye tracking to enable flexible cross-referencing. Theodor Holm Nelson popularized the term "hypertext" in 1967. Hypertext allows users to access information non-linearly by clicking on links within documents. It has advantages like easy reference tracing, information structuring and customization. Potential issues include disorientation when following links. Hypertext finds applications in various areas like business documentation, online references, personal learning tutorials, and computer-assisted language learning.