Are you training your customers to delete the email you send?
My grocery store has me trained. They have one of these loyalty rewards programs where I receive a point for every dollar I spend. Every two weeks they send out a flyer (via mail) and it has 50 products advertised, each with 10 or 15 bonus points. They also always have two coupons that are for 2500 points each if you spend $95 or more.
Over the past couple years I've discovered that all the coupons suck, except the 2500 point coupons. So like clockwork, every two weeks I cut out the two good coupons. The rest of the coupons are in the garbage. I've never use them. I can't even remember the last time I glanced at the offers.
So here's my point. Customers can be trained. Amazon sends me an email, I'll read it, and if that email is of value I'll remember. Because the last email was of value, the next email I receive from Amazon I'll read. If there is value there, I'll read the next email. It spirals up. I start to predictably open the emails from Amazon.
The opposite happens at some wineries. An email is created. Rather than creating a specific value proposition for a specific target audience, they send the email to their entire consumer list (after all, it costs almost nothing to send the email out). Some customers don't see value in the email. Another email is created and it goes out to the entire email list again. Again a group of customers don't see any value. The winery has trained a group of customers to ignore the email.
Tonight we analyzed the open behavior on one million emails sent over the past two year where the customers had been emailed 5 or more times. After 4 emails there was an 91.4% chance the customer had been trained (and responded to all future emails in the same manor).
So to put my point in a few sentences. Customers are predictable. If they are opening your email and responding by clicking back, you should probably keep doing the same thing. If they are consistently ignoring you email, it might be time to change what you're doing.