Or hope you have engaging enough content that they click through one of your links. For example, email newsletters like HackerNewsletter are essentially just l

Or hope you have engaging enough content that they click through one of your links. For example, email newsletters like HackerNewsletter are essentially just links, so there is a good chance a person will click through and be counted as an "open" (as well as a "click"). And the tracking pixel of course. Some clients auto-show images, some don't. Some people allow emails to show images, some people refuse. It's all just a "best guess".