It will go down in history as "X, formerly known as Twitter."
See also:
The artist formerly known as Prince and Pluto, the heavenly body formerly known as a planet.
See also:
The artist formerly known as Prince and Pluto, the heavenly body formerly known as a planet.
Who of course, went back to using the name Prince once his contract dispute was over, which meant he could be the artist formerly known as the artist formerly known as Prince.