. The high internet users in Indonesia, with a number of user penetration of more than 34.9%. The internet user has a diverse demographic that is spread throughout the territory. Seeing this potential can be in the know on the website advertising potential. To optimize that ads on a website can be relevant to the user required a design method. Ontologies are used as domain knowledge in the delivery of relevant ads. Ontology is built through a process of conceptualization, adapted from methods Gruninger and Fox and Methontology. Conceptualization resulting from such methods, evaluation methods OntoQA (Ontology Quality Analysis). Measurements were carried out to produce a quality score potential knowledge with details Relation richness value of 0.451, the value of Inheritance richness of 4.857 and a richness Attributte value of 6.75. Value Relations shows the richness of the information provided ontology categorized at level sufficiently rich in knowledge. Value Inheritance richness showed ontology includes areas of general knowledge. While the value Attributte describe the richness of the information provided.