Facets, get your luver-ly facets

I've been pondering faceted metadata for a while, reading about Ranganathan, bits and bobs on boxes and arrows about implementing it on a site and so on and so forth, and I've reached the stage where I'm a tad blocked on the subject.

Faceted metadata is based around the fact that items share similar facets .i.e.
Diamonds might have an item, Gopal diamond whose facets are

• colour (value - pink)


• clarity (value - twinkly)


• carat (value - 12)

All diamonds will share these facets and can be defined (and therefore organised, browsed and searched) by them.

Maybe it's just me, but - because of this very fact - facets only seem to be useful where there is a great degree of homogeneity between items - i.e. where every item on a site shares pretty much the same facets. This seems to be great for ecommerce sites where an item has a name, price, and other similar attributes ("facets") to it that are reasonably rigid, but not so useful for, say, a corporate site where items might be more heterogenous.

For this reason, certainly for documents, I just wonder whether a more rigid metadata set is better for this sort of site, Dublin Core for instance. I'm just not sure if I'm being short-sighted and have missed a trick somewhere with facets... Maybe I should try and read about topic maps now to cover all the bases.

UPDATE 11 September 2003

Well as an update, it's worth reading Tanya's implementation of facets with Movable Type at her site Pixelcharmer - the only drawback I can see (as with all facets) is that an item can only belong to one topic. This is because facets should be mutually exclusive - but I can think of instances where an article could belong to both "XML" and "CSS" at the same time. Still, it's a very nice job indeed (and partly answers my question)...