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.
Bathtub hoax
On December 28, 1917, an article titled "A Neglected Anniversary" by H. L. Mencken was published in the "New York Evening Mail". It claimed that the bathtub had been introduced into the United States as recently as 1842, the first ones having been made of mahogany lined with lead. The article went on to describe how the introduction of the bathtub was initially greatly discussed and opposed until President Millard Fillmore had a bathtub installed in the White House in 1850, making the invention more broadly acceptable.