It mostly grew out of frustration that no one had built a good, social movie experience. They knew they had to do it ourselves. This was circa 2010. Essentially what they wanted was the follower model from Twitter and Tumblr combined with a cast-crew database and film diary. Lists were also in the thinking from the start.
Letterboxd was launched as a social app focused on sharing opinions about, and love of, film, and is maintained by a small team in Auckland, New Zealand. The site is meant for sharing its members' tastes in films.