[mongol]

Was it Slashdot that "invented" the nickname Anoynmous Coward? Or did it exist before?

[exikyut]

Unfortunately Trends only goes back to 2004, but... https://trends.google.com/trends/explore?date=all&q=%22anony...

[mongol]

Slashdot's use of it certainly goes back to the previous century though..

[Fnoord]

They innovated it for sure but before that the more neutral term "Anonymous" was used for a long time (although anonymity is a relative term). The Coward part makes it part of Slashdot's cultural heritage.