Open Rate or also referred to as the read rate, is the number of emails that are opened in an email marketing campaign as a proportion of the total number of emails sent. Open rates can occur in two ways; one is intended for physical mail and the other for electronic mail.
Open rates are typically tracked using a transparent 1×1 pixel, or small transparent tracking image, that is embedded in outgoing emails. When the client or browser used to display the email requests that image, then an “open” is recorded for that email by the image’s host server. The email will not be counted as an open until one of the following occurs: the recipient enables the images in the email or the recipient interacts with the email by clicking on a link.
The “open rate” for physical mail is difficult to quantify when compared to electronic mail but it is extremely important to the success or failure of response-oriented mail (marketing, billing, recovery, renewals, etc.). In fact, physical mail open rates can, and should, be further segmented and defined: the rate at which a piece of mail is opened within 30 days as determined by the recipient’s conscious and sub-conscious judgments about the un-opened mail piece; this decision is often made in 3–5 seconds. Though physical mail, also known as “snail mail” or direct mail, may be overshadowed by email marketing, it’s still considered an important part of some business’ marketing strategy.