In this work, we present a proposal for characterizing the OWL ontologies available on the Web from a significant sample. We have conducted a study to review the specific characteristics of these ontologies paying attention to features which can be important from the point of view of the ontology alignment: language, sizes, number, and kind of entities that are represented in them. As a result, we offer some statistical data that can be helpful in order to understand the current situation of OWL ontologies in the Web and, therefore to guide the process of taking decisions when developing applications for aligning them.
