Mailer app is capable of automatically counting email message views by the recipients. To enable this kind of report, simply add any image to your message.
Be sure to upload an image from your computer rather than specifying a link to it! Otherwise the built-in message views counter will not work.
When an embedded image is displayed in the recipient's email client, it is downloaded from your server, and the Mailer app registers each such download, and shows it on a chart.
Please note that not all views can be tracked using this feature. Many users have images disabled in their email clients and, therefore, no image download occurs, and the message view is not counted.
However, this is a useful feature to allow you to evaluate the approximate number of recipients who have viewed your message and compare it for several newsletter with different design and content to analyze their efficiency.