I'm hearing more and more questions over time from founders, execs and marketers at startups about NPS (net promoter score). If you are not familiar with NPS, check out this overview and my interview with the creator of NPS. We used NPS extensively at HubSpot starting when Jonah Lopin implemented it around 2009 (he's now founder of Crayon, check it out if you do any marketing or design work - I'm an advisor and investor). NPS can be a very valuable tool in measuring customer happiness and the underlying growth potential of your startup, if it is used properly. Unfortunately, from the questions I have been getting, I worry startups are misusing NPS, so here are some of my thoughts.