Most Semantic Web or AI discussion is about finding adequate information with intelligent retrieval systems. Ontologies are used to identify content based on formalized knowledge, either by automatic statistical reasoning or by human annotation. Usually, knowledge management applications concentrate on one ontology for a certain area of expertise to provide retrieval systems for a specific group of users aka experts.
The Semantic Web will be very much about communication/interaction between different, even contradictory world views. Ontologies are the computational equivalent to value systems because they define terms/concepts and their relationship. For future content or knowledge management systems, this means, that they must be able to handle multiple ontologies. Especially, if we think of innovation as based on new insights, multiple ontologies applications become interesting to knowledge based economies. Just imagine applying different, maybe contradictory ontologies aka world views to a specific or global information pool.
One major prerequisite for such a sophisticated system of multiple and interactive realities and interpretations based on ontologies, is that ontologies become easy and inexpensive to create. Also, they need to be transfered between applications. In this respect, Weblogs could server as an initial start, because here individuals categorize their Weblog entries based on self-made, usually flat structure of categories. Although this does not meet the requirements of ontologies, it would be interesting to see Weblogs not only interact on the basis of Weblog entries (e.g. via trackbacks), but also related to their catalogs/subjects/categories.