The Semantic Web movement has led to the publication of thousands of ontologies online. These ontologies present and mediate information and knowledge on the Semantic Web. How to provide tractable reasoning services for fuzzy and crisp ontologies has been a pressing research problem over the last five years. In this paper, we present a reusable semantic infrastructure that comprises a tractable reasoning system TrOWL, an ontological search engine ONTOSEARCH2 and a folksonomy extension component Taggr. We show that such an infrastructure can be used to support different ontology applications with tractable reasoning services by making use of tractable profiles in OWL 2 and some of their fuzzy extension.