If I was the target I would prefer a newsletter to contain weblinks for further reading after an initial title/introduction in the email body. This way you would be getting multi-dimensional data on each genuinely interested user. Weather they opened it or not it does not matter. Have they expressed interest in visiting the stories/products? That's what matters.Then keep changing the stories to see if you get any heartbeat. Deleting the newsletter unread, straight from the queue perhaps it's because they have the impression it is of no interest whatsoever. In which case I find it easier to unsubscribe and get rid with this hassle. Why would I delete email unread?: Tacky titles, past experience as being useless or with aggressive marketing, marketing lingo, excessive company logos, headers, tons of legal footer, idiots.