|On December 10, 2016, about a month after his election, Donald Trump used the term 'fake news' for the first time in one of his famous tweets. A few months later, in October 2017, he boasted in an interview on Fox News that he had really started "the whole fake news thing".
Donald Trump is right: he really started something. While he can't seriously claim authorship of the term, it has indeed become quite popular since he turned it against CNN or New York Times reporters. This popularity is due to the confusion that he is creating.