I stand corrected. My mistake was assuming that the friend who introduced me to it in 1991 was representative: he called it net news and in 1993 or 1994 when people started calling it Usenet, he told me that no one in his experience called it that. The first people I observed to call it Usenet were mainstream news articles. When web sites owned by mainstream media started appearing, the phrase "net news" appeared on more than one of their mastheads / headers.