Whiteboard
Whiteboards became commercially available in the early 1960s, but did not become widely used until 30 years later. Early whiteboards needed to be wiped with a damp cloth and markers had a tendency to leave marks behind, even after erasing the board. Dry-erase markers for whiteboards were invented in 1975.
History of tablet computers
In 1996, The Webbook Company announced the first Internet-based tablet, then referred to as a Web Surfboard, that would run Java and utilize a RISC processor. However, it never went into production.