MS began using [MP3] in 1998. The FSF says â€œthey would have been safeâ€ [using Vorbis in 2000]. That overlooks the inconvenient fact that [Vorbis 1.0] was not released until July 2002. Itâ€™s hard to imagine how MS could have chosen the â€œsafeâ€ open-source option when it didnâ€™t exist yet.
Ed Bott on the FSF’s campaign for OggÂ (my edits for brevity)