Would any of your customers hold onto a marketing letter you sent for over 50 years? Seems unlikely, right? But that’s exactly what my parents did. Read the full article to discover all 6 secrets to relational marketing that were hiding in this one simple letter sent over 50 years ago. And how, if you implement even 1 or 2 principles in your marketing, you can create the kind of genuine, long-lasting relationships that drive loyalty and referrals.