1965, Side-by-side connected comparison of parallel documents
1972, Transpointing windows
1999, PYXI viewer by Ka-Ping Yee
2014, OpenXanadu by Ted Nelson and Nicholas Levin
Parallel documents / Transpointing windows
Deep versioning and re-use (transclusion)
JS implementation of Stretchtext
ZigZag database system
Book and website with essays about future forms of reading. Free to read online.
Develop tools for non-linear text production, information search and new forms of knowledge organization. They experiment with interface concepts and ways of associating information to enable new forms of dealing with knowledge, often especially personal knowledge systems.