Dynamic content can be delivered via email. Email messages include HTML content with one or more hyperlinks referring to a network-connected dynamic content server. The hyperlinks are accessed upon rendering of the email on a client device, triggering a request to a dynamic content server. The dynamic content server determines a content item to be served in response to the request. The dynamic content item determination may be based on factors including the identity of the requester, the email communication in which the hyperlink is embedded, recent activities or behavior on the part of the requester, and/or known preference or demographic information associated with the requester. The request can be directed to a selected content item stored within a content delivery network, for transmission back to the requester and display to the user within the email.