Miley Cyrus was supposed to be on the December cover of Vogue, but Anna Wintour said no thanks. From the Daily Mail:
Miley Cyrus's crude dance at the MTV Video Music Awards has cost her the coveted cover slot on American Vogue. The 20-year-old, right, was photographed for the December issue as editor-in-chief Anna Wintour had been eager to champion her as a new fashion icon. But she soon changed her mind after witnessing the singer perform her overtly sexual routine in latex bra and knickers.

"Anna found the whole thing distasteful," a source says. "She decided, based on Miley's performance, to take the cover in a different direction."
It's either Anna being a prude or Miley is just too scandalous. Which is it?