The Email marketing funnels are being changing during last years. The most commonly used is the following:

 

 

Later people fount out that there is another important metric, mainly with the landing of the called “viral marketing“, forwards and/or tell a friend. This new metric added complexity to the funnel and each Analytic Professional opted for a different design. The most commonly used (at least the one I saw the most) is the following one (forwards are inserted into the funnel in different places):

 

The problem with the above displayed funnel is that Forwards aro not part of the conversion process of a single user. I mean people can convert whether they forward the email to their friends or not. Forwards or “Tell a friend” (the viral composition of the email marketing piece) increase the quantity of people that receive the email and begin with the conversion process. So the funnel should look like the following one:

 

The “second” funnel is expected to generate better conversion rates since are emails send by users to their friends which are supposed to be interested in the contained information.