"Prior value" is a meme that ought to fly around the email marketing world and become firmly lodged in our consciousness. Your next email is can never be more interesting than your last email.
Email Marketing Best Practices: Email Marketing and the Concept of Prior Value, 2007-Feb-28, by Chris Baggott
I learned a new term today from Stephanie Miller of Return Path. Prior Value. I can’t remember the exact stat, but the basic premise from her research is that the top reason given for a subscriber engaging with an email was “Prior Value”. The value I felt I got from your previous email. Brilliant.