A domain classifier develops and maintains relevance data about specific domains based on historical relevance data and source context data. Such data may be used to classify the user's interest in attempting to visit a specific domain and thereby redirect the user to a website expected to be aligned with the user's interest. In various implementations, the historical relevance data is derived from source context data and/or post-visit user behavior collected from previous attempts to visit a specific domain. The source context data collected from the current visit may also be used as source context-factors to influence domain classification. Based on such historical and current source context factors, as well as the domain address provided in the user's navigation request, a domain classifier consults the historical relevance data and provides the user with Web content that is identified as likely to be relevant to the user's interests.