1. A method of classifying web content, implemented on one or more computer processors, the method comprising: using at least one of the processors, receiving content of at least one web page; using at least one of the processors, determining a first property of a plurality of properties associated with the web page at least in part by identifying a keyword in the content of the web page, the first property comprising static content associated with the web page, using at least one of the processors, determining a second property of the plurality of properties at least in part by executing active content associated with the webpage in a sandbox environment, the second property comprising the active content; using at least one of the processors, storing the first property and the second property in a database of web page properties; using at least one of the processors, comparing at least one definition from a definitions database to the first and second properties, wherein a particular definition contains a logical expression relating the first property and the second property; using at least one of the processors, associating the web page with at least one category, the category associated with the particular definition, wherein said category is indicative of the active content associated with the web page; wherein the logical expression comprises at least one term comprising a relationship of at least one web page property to at least one other value; and wherein the at least one other value comprises a constant value matching at least a portion of the content of the web page.