This example has a double whammy - a direct-marketing email without a call to action, and some invisible text. In chapter three of my book I raise what I think is the basic issue of putting dark text on a light background [as I do on all my sites] to make it easy to read. Indeed, I give my students a 'bad web page' exercise with an example of light text on a light background and they usually scoff at the idea of a commercial web developer making such an error - well, take a look at this:
Furthermore, the 'hidden' text is the call to action - arguably the most important words on the email. Ho hum.