Nike's "Just Do It" didn't just happen.
The tagline and the brand that's been built around it was developed through a process–and a fairly long one, at that. It most likely entailed numerous interviews in focus groups with athletes and aspiring athletes to understand not only their wants, needs and thoughts about Nike, but what drives and inspires them to compete and/or workout. The process included market, competitor and SWOT analyses, demographics, consumer psychology studies and a host of other data and research.