For example, one search request can correlate many aspects of demand and supply. Profiles of books or videos, for example, can be matched with profiles of stores or people with similar interest profiles. Any Virtual Community is some kind of a Special Interest Group, a 'SIG'. It is a set of persons with significant common interests and goals, defined by desire among its members to communicate with each other. Identical principles apply to all communications within Special Interest Groups.
Intranets are more coherent than the Internet because they are more focused.
General libraries are not coherent collections because they cover the gamut. A library filing system is simply a coherent approach to an incoherent collection, but it can be used within postcoordinate thematics. For an example of how to use the Dewey Decimal system. Categories are never objective, and never sufficiently detailed for our interests, goals, or resources. Categories are relics of print technology and historical academic conventions.