The period before an artist becomes Advanced is called the "Overt" stage. It is called this because during this period the artist is trying to be innovative (or "weird" in Advanced parlance) in an obvious way. A good example of this would be David Bowie's Ziggy Stardust days. It doesn't take much imagination to recognize that a guy in kabuki makeup with shaved eyebrows wants to be seen as weird. (Of course there were hints of Advancement in his Overtness: you can't help but appreciate a space-alien rocker playing an acoustic twelve-string onstage, plus the music happened to be fantastic.) But what were we to make of the cover of "Dancing in the Streets" he did with Mick Jagger? Was that weird? If so, what kind of weirdness was it? What was he hoping to accomplish? Your guess is nearly as good as mine.
Please don't misunderstand: Overt does not mean "bad." It just means that the artist hasn't Advanced yet. No one could ever say The Rise and Fall of Ziggy Stardust and the Spiders From Mars was bad, but it was definitely Overt. All Advanced Artists go through an Overt period, and it is during this period when they make their groundbreaking, brilliant music. In other words, the music is great, it's just not Advanced. So when I say that Radiohead are Overt, I don't mean that they aren't any good. They are, and if they split up, Thom Yorke could become Advanced. But if that never happens and they just keep making interesting music they will be one of the all-time-great Overt bands.
One final thing about Overtness: There are plenty of Overt artists, but just because you're Overt doesn't mean you can become Advanced. You have to be Overt and great, too, and for at least fifteen years. Karen O of the Yeah Yeah Yeahs could make music for 50 years and never be Advanced because her band just isn't good enough (plus she misbehaved at my karaoke show).