For those of you who need to design an information architecture - definitely take a look at these articles:
By the way - here is the definition that Wikipedia provides - http://en.wikipedia.org/wiki/Taxonomies
Taxonomy is the practice and science of classification. The word comes from the Greek τάξις, taxis, 'order' + νόμος, nomos, 'law' or 'science'. Taxonomies, which are composed of taxonomic units known as taxa (singular taxon), are frequently hierarchical in structure, commonly displaying parent-child relationships.
Some people might argue that a top-down approach for classifying information is not the way to go - these are probably the ones who prefer to talk about Folksonomies. Here is another Wikipedia definition - http://en.wikipedia.org/wiki/Folksonomy
A folksonomy is a user generated taxonomy used to categorize and retrieve web content such as Web pages, photographs and Web links, using open ended labels called tags. Typically, folksonomies are Internet-based, but their use may occur in other contexts. The folksonomic tagging is intended to make a body of information increasingly easy to search, discover, and navigate over time. A well-developed folksonomy is ideally accessible as a shared vocabulary that is both originated by, and familiar to, its primary users. Two widely cited examples of websites using folksonomic tagging are Flickr and del.icio.us, although it has been suggested that Flickr is not a good example of folksonomy.
Those of you working with SharePoint Server 2007 as a solution platform for Knowledge Management and Document Management, definitely take a look at the taxonomy/tagging starter kit as well as Rapid For SharePoint. One of the things with SharePoint is the fact that it is just to simple to use out of the box - you can dive straight in without thinking. If you want to make your SharePoint project succeed, make sure that you don't dive straight in but that you plan your information architecture beforehand.