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.
Whiteboarding
Electronic whiteboarding was included at least as early as 1996 in the CoolTalk tool in Netscape Navigator 3.0.