1. A computer-implemented method of categorizing a uniform resource locator (URL) based on web content associated with the URL, the method comprising: receiving a URL associated with web content from a first collection source of a plurality of collection sources; categorizing the URL if the URL is determined to contain a known malicious data element; if the URL is determined not to contain a known malicious data element, retrieving data associated with the URL, the data comprising: a frequency of requests for the web content by a second collection source of the plurality of collection sources; a priority corresponding to the first collection source, the priority determined based on a manner by which the collection source retrieves the URL; an indication of whether the web content comprises executable content; and determining a category for the URL based on at least a portion of the data associated with the URL.