It is not a secret that we love Net Promoter Score at Visible. The term "Net Promoter Score" has a corporate ring to it, making it seem like something that startups don't need to worry about until they "grow up". In reality, implementing a customer happiness metric like NPS is one of the most important (and easiest) things your startup can do once you begin to acquire customers. An accurate NPS helps you gain an understanding of how loyal your customers will be over the long term and what kind of word of mouth growth you can expect. But it isn't just the happiness of your customers you should be worried about.