dug 
University of Pennsylvania are introducing a tagging system to complement their library’s traditional structure:
PennTags - When card catalogs meet tags. Many-to-Many
I know us advertising types don’t think of library science as particularly cool, but example is relevant to what we do.
Put it like this: It would be like consumers collaborating with brands to design and build information architectures that are relevant to each consumer as an individual. Traditional segmentation struggles to deliver co-creation’s “experience of one” and this is a nice example of how that might work in the future (make that later this afternoon).
(Thanks Mr Monkchips)