communities of interest, where descriptors have to be specific, exact, unambiguous...
tags are lazy, sloppy, hasty. taxonomies are cumbersome (cheap shot), unintuitive... but also unambiguous.
how to make tags for c.o.i.s unambiguous, precise? reference to the schema needed to define terms. building better schema, yes, but also building better ontological tools, meta-schematic maps that define where the references are, what they refer to (and when), and the context necessary to decide on one over another.
much more to learn.
how can library thing help us to make one instance of "rock" mean stone, and another instance mean the music? are tags a black hole? and they, don't they, still ultimately depend on the occasional human pruning, picking the "fucks" and "goddamns" from the record page once LT is integrated into your ILS?
we need better tagging tools.
this whole thing -- it has to be a 'how can we make this work better for us and our patrons' thing rather than a 'ooooh, i du-nnnnnnnnnnoooooo, should we or shouldn't we even dooooooo this' thing.
and hell yes. we need to do this. but smartly.