1) Madonna is considered a postmodern artist because she frequently changed her musical style and image over her career to keep up with trends.
2) She released her album "The Next Best Thing" in 1998 which featured different musical styles than her previous work such as electronic beats, folk guitars, and heavy vocoder usage.
3) Throughout her career, Madonna provoked controversy through her use of religious symbols in music and a sexually explicit book, though she later attempted to soften her image.