1. A computerized method of collecting potentially problematic Uniform Resource Locators (URLs), the method comprising: receiving, via an email filtering system, an email message destined for a recipient email address, the email filtering system connected to a destination email server corresponding to the recipient email address; identifying, via an electronic processor, a URL from the email message; analyzing, via the electronic processor, the email message on the basis of one or more of the URL, the email message subject, format of sender and recipient address of the email message, or text within the email message so as to classify the email message as either a first type of email message or a second, different, type of email message, wherein the first type and the second type are mutually exclusive; if the email message is classified as the first type of email message, transmitting a message from the email filtering system to a separate URL filtering system, which controls access to URLs via a public access network, the message requesting the URL filtering system to categorize the URL, wherein the message is transmitted independent of a request to access the URL; and if the email message is classified as the second type of email message, not transmitting a message from the email filtering system to the URL filtering system requesting the URL filtering system to categorize the URL.