Four years ago today, former PR professional Justine Sacco posted a tweet to her 170 Twitter followers that would have a disastrous effect on her career, which has frequently been cited as an important case study in the power of online shaming ever since.

Two weeks after it was reported that the new editor-in-chief of Marvel comics had used a Japanese pseudonym early in his career, C.B. Cebulski apologized.

Though the concept has only spawned a few variations, the hashtag casting Sex and the City's Charlotte as a woke warrior has been a hit online

Puts new meaning to the words "I think, therefore I am.