1. A computer-implemented method for generating at least one custom email message based, at least in part, on input from a user of a computer system, the computer system having a display, the method comprising acts of: A) presenting, to the user in the display of the computer system, an editor interface displaying an initial approximation of an email message comprising a plurality of content blocks; B) accepting, through the editor interface, at least one customization of at least one of a content of at least one of the plurality of content blocks and a layout of the plurality of content blocks; C) displaying through the editor interface a customized approximation of the email message based, at least in part, on the initial approximation of the email message and the at least one customization; and H) rendering a live version of the custom email message by, at least in part, merging partner information from a remote website into a promotion block of the plurality of content blocks, wherein the rendering includes generating a representation of the custom email message based, at least in part, on a document object model representation of the custom email message.