The results have shown that around 410px would be our ‘email fold’, receiving 12% of clicks within the first 25% of the email. Although there did continue to be an even spread of clicks between 410px and 1600px, with 80% of recipients continuing to engage this far down the email.
Email Fold test: https://actionrocket.cmail20.com/t/ViewEmail/j/1A2F363201FB56712540EF23F30FEDED/F074182C6690C06A40EE66FE10287772
Results: (More info ) http://www.emaildesignreview.com/action-rocket/results-from-our-emailweekly-test-4083/