Customer Loyalty

Today, I observed that companies actually care about existing customers and not just getting new customers. The past few years, it seems people have been emphasizing the number of new customers or users. This can't be the most significant factor though; the existing customer base must be just as important if not much more. But with a number of over a billion, the number of users on Facebook, it's hard not to compare numbers. But what I take away from that number is not much though. The more important number is the number of active or engaged users. These are the people that will keep your product relevant in the market.
For example, I called customer service at T-Mobile to upgrade my phone to the Galaxy S III. Since Walmart advertised the upgrade for only $200 compared to the $280 (after rebates) that T-Mobile was advertising, I wanted to see if they would price match it (Many stores do it, take advantage if you can!). The customer service representative said they don't price match, but called the Walmart store to see why I can't upgrade my phone there since I was an authorized user (They require the primary account holder). After, they checked what they could do for me. Then realizing we've been using T-Mobile (Omni-point, Voicestream) for over 12 years, she offered me an outstanding deal, even better than the $200 Walmart was offering. It was actually a painless experience dealing with customer service, which can't be said by many companies.
With such great service throughout the years, I recommend T-Mobile to anyone especially in metro areas. And this is the most important aspect of a product/service, to make sure that the existing customer is satisfied. This leads to much more and the benefits are endless. Marketing becomes much easier since the users are doing all the work. And "Word of Mouth" is probably the best type of marketing. People usually trust the opinions of people they know and personal reviews from people you trust/know are drastically more effective than random online reviews.
One thing I feel happens much too often is companies take their current customer base for granted and stress the importance of new users way to much. I fully understand that it's necessary to offer special deals to attract new users but I would like to see more done for loyal users.