It appears that he is saying that purely bottom up folksonomies don't increase our confidence that the information we discover through them has authority but rather that we need structure to increase find-ability and thereby confidence in what we find. What he doesn't clarify, other than a reference to Wikipedia's board, is where the structure comes from and who decides it.
He seems in the last paragraph to be implying that we WILL eventually work out a way to derive authority from emerging structure rather than imposed structure but that may be me just hearing what I want to hear!
Of course, we must also recognize the power that devolves to the individual in an open media landscape that enables us to select our sources and choose our news. In today's Google economy, we are increasingly becoming our own authority.
The real upheaval lies just ahead, as a generation of school kids (and their teachers and librarians) struggle to reconcile traditional notions of education and objectivity and authority with the constructivist web of social facts and collective intelligence where folksonomies flourish and the truth is a virus of many colors. I can hardly wait.Thanks to Jon Husband for pointing me to this cracker.