Tom Coates writes:
The concept is really simple – there are concepts in the world that can be loosely described as being made up of aggregations of other smaller component concepts. In such systems, if you encourage the tagging of the smallest component parts, then you can aggregate those tags up through the whole system. You get – essentially – free metadata on a whole range of other concepts.
The upshot of all of this is that you start getting a way of navigating between a whole range of different concepts based on these combinations of tags and ratings. The tags give you subject related metadata, the ratings give you qualitative metadata and from this you can start finding new ways to say, “If you liked this song, you may also like this album, network, album or artist”. You can start to generate journeys that move you from network to that networks most popular songs, through to the best albums on related themes (or which conjure similar moods or associations even if they’re by radically different artists) and so on.