Patent ID: 8473611

Claim:
A method, comprising: receiving, at a content filter of a computer system, a request for content, the request including a referrer of the request; and permitting or not permitting the content to be downloaded according to whether or not a root site associated with the referrer of the request is a permitted site by: determining, based on the referrer, whether a root site associated with the referrer is a permitted site and, i. if the root site is not a permitted site, then not permitting the content to be downloaded; otherwise ii. if the root site is a permitted site, then determining whether or not a referred site specified by the referrer is a permitted site, and a. if-the referred site is a permitted site, then permitting the content to be downloaded, otherwise b. if the referred site is not a permitted site, then determining whether or not the referred site is in a semantically equivalent content category as the root site, and x. if the referred site is in a semantically equivalent content category as the root site, then permitting the content to be downloaded; otherwise z. if the referred site is not in a semantically equivalent content category as the root site, then not permitting the content to be downloaded.