Feature modeling has been proposed as an approach for describing variable requirements for software product lines. In this paper, we explore the relationship between feature models and ontologies. First, we examine how previous extensions to basic feature modeling move it closer to richer formalisms for specifying ontologies such as MOF and OWL. Then, we explore the idea of feature models as views on ontologies. Based on that idea, we propose two approaches for the combined use of feature models and ontologies: view derivation and view integration. Finally, we give some ideas about tool support for these approaches.