How many times do you "touch" or inteact with your customers? Your customer loyalty is correllated with how often you interact with them. Think of each 'touch' as a discrete interaction. So for example, at a gas station - the customer visits (1), comes inside (2), purchases gas and a soda (3) and leaves (4). Each time, you have a chance to make it a good experience. For example, if the station is spotless, the workers greet you as you enter - but the actual transaction is terrible - the customer won't remember the rest.
If you increase the number of touches, whether by a newsletter, or a call or even visiting the customer site, you can increase the possiblity of creating a loyal customer.
Of course the opposite holds as well - each touch is a chance to screw up. People often say they don't penalize a waitress's tip if the food tastes bad - but I'd like to hear from waitresses on whether that is true or not!
As a entrepreneur, you can have all the enthusiasm in the world for what you do, but you can't control every touch point. You can increase the number - but be sure you watch the quality. Nothing comes off more fake as the hold message that says "we are sorry for the inconvenience, thank you for waiting" (why not solve your concern for me by having more staff available?).
Finally, by breaking down the touch points between you and your customer, it allows you to better manage and track how well you are doing.