A system for categorizing a plurality of network resources, the system comprising: a computing platform for interfacing with the computer network, the computing platform including computing hardware of at least one processor, data storage, and input/output facilities, and an operating system implemented on the computing hardware; and instructions that, when executed on the computing platform, cause the computing platform to implement: a categorization engine configured to analyze collected properties of a network resource to determine applicability of various predefined categories to that network resource and to assign at least one category from among the predefined categories to that network resource according to a determination of applicability of the at least one category to the network resource; and a categorization interval adjustment engine operatively coupled to the categorization engine and configured to dynamically adjust a resource-specific time interval for causing the categorization engine to re-categorize each one of the network resources based on a plurality of previous categorization results for that network resource, such that different network resources will be associated with correspondingly different re-categorization intervals wherein: the various predefined categories include a category indicating malicious content present in a given network resource, and wherein the categorization interval adjustment engine is configured to dynamically adjust the resource-specific time interval such that: in response to a categorization of malicious content in the network resource, the time interval is reduced by a first increment; and in response to a categorization of non-malicious content in the network resource, the time interval is increased by a second increment that is smaller than the first increment. a computing platform for interfacing with the computer network, the computing platform including computing hardware of at least one processor, data storage, and input/output facilities, and an operating system implemented on the computing hardware; and instructions that, when executed on the computing platform, cause the computing platform to implement: a categorization engine configured to analyze collected properties of a network resource to determine applicability of various predefined categories to that network resource and to assign at least one category from among the predefined categories to that network resource according to a determination of applicability of the at least one category to the network resource; and a categorization interval adjustment engine operatively coupled to the categorization engine and configured to dynamically adjust a resource-specific time interval for causing the categorization engine to re-categorize each one of the network resources based on a plurality of previous categorization results for that network resource, such that different network resources will be associated with correspondingly different re-categorization intervals wherein: the various predefined categories include a category indicating malicious content present in a given network resource, and wherein the categorization interval adjustment engine is configured to dynamically adjust the resource-specific time interval such that: in response to a categorization of malicious content in the network resource, the time interval is reduced by a first increment; and in response to a categorization of non-malicious content in the network resource, the time interval is increased by a second increment that is smaller than the first increment. a categorization engine configured to analyze collected properties of a network resource to determine applicability of various predefined categories to that network resource and to assign at least one category from among the predefined categories to that network resource according to a determination of applicability of the at least one category to the network resource; and a categorization interval adjustment engine operatively coupled to the categorization engine and configured to dynamically adjust a resource-specific time interval for causing the categorization engine to re-categorize each one of the network resources based on a plurality of previous categorization results for that network resource, such that different network resources will be associated with correspondingly different re-categorization intervals wherein: the various predefined categories include a category indicating malicious content present in a given network resource, and wherein the categorization interval adjustment engine is configured to dynamically adjust the resource-specific time interval such that: in response to a categorization of malicious content in the network resource, the time interval is reduced by a first increment; and in response to a categorization of non-malicious content in the network resource, the time interval is increased by a second increment that is smaller than the first increment. in response to a categorization of malicious content in the network resource, the time interval is reduced by a first increment; and in response to a categorization of non-malicious content in the network resource, the time interval is increased by a second increment that is smaller than the first increment.