US Patent 10096001 Email data collection compliance enforcement

A system comprises content caching circuitry of a first email subsystem, and privacy enforcement circuitry of the first email subsystem. The privacy enforcement circuitry is configured to, after the reception of the email message by the connection handler circuitry and before relaying of the email message to a second email subsystem, detect tracking code in the email message; and replace the detected tracking code with replacement content. The tracking code comprises a first uniform resource locator (URL), and the replacement content comprises a second URL. The content caching circuitry is configured to: determine whether content stored at the first URL is wanted or needed; and not fetch the content from the first URL if the content stored at the first URL is not wanted and not needed.