Discussion, observations, and comments from the 2009 Conference on Semantics in Healthcare and Life Sciences. CSHALS is an official conference of the International Society for Computational Biology (ISCB).
Mark Wilkinson exposes just parts of his ontologies (e.g., single OWL classes) as web services, rather than focusing on SPARQL endpoints. This allows much finer control over what he's doing than you could otherwise get.
I like to distinguish between ontologies that model information and ontologies that model "the real world" - in my experience, the former is very useful for driving UIs, data collection, linking data, etc. and the latter is very useful for taxonomies and enabling semantic search, navigation, etc.
One great thing about working with semantic technologies is the wealth of tools available for free. There is much to be done, certainly, but there is much that has been done already and there are ample opportunities to contribute.
Open Biomedical Annotator: A web service that converts a piece of free text (e.g., a journal abstract of 200 to 300 words), into a set of recognized and related ontology concepts and terms. - http://bioontology.org/tools...