Definition: Open Rate is an email marketing metrics that measures the percentage rate at which emails are opened. Though it is a general indicator of subject line effectiveness, it can be a misleading metric for online marketers.
According to Mailchimp benchmark reports, which include both small and Fortune 500 clients, email open rates average between 15% and 30% across most industries. Personal interest topics (religion, hobbies, photos, etc.) trend higher while marketing topics (ecommerce, coupon offers, and so on) trend lower. Daily deals have the lowest open rate of all.
In general, companies have no reason to try and increase their open rates above the average for their industry - doing so sounds like it could be good for business, but it's so difficult that most companies will never see a return on their investment. On the other hand, if an individual company's rate is significantly below average, then they know things can be done to improve it (and it becomes worthwhile to make that investment).
Ultimately, it doesn't matter how many people end up reading a company's messages - what matters is how many of them ultimately advance through the sales funnel and convert into paying customers. An email could be opened the majority of the time and lead to user frustration with the sender; converseley, emails with a low open rate could have a higher conversion rate.
Open rate can be used as a complementary metric when A/B testing subject lines within an email campaign. It can also be an indicator of brand goodwill over time — when open rates increase, consumers trust may be increasing.
Getting a high open rate isn't about doing things right so much as not doing them wrong. Several common mistakes can lead to lower-than-usual open rates, so consider checking your current campaigns for the following: