Development of Tumblr began in 2006 during a two-week gap between contracts at David Karp's software consulting company, Davidville (housed at Karp's former internship with producer-incubator Fred Seibert's Frederator Studios, which was located a block from Tumblr's current headquarters). Karp had been interested in tumblelogs (short-form blogs) for some time and was waiting for one of the established blogging platforms to introduce their own tumblelogging platform. As no one had done so after a year of waiting, Karp and developer Marco Arment began working on their own tumblelogging platform. Tumblr was launched in February 2007, and within two weeks the service had gained 75,000 users. Arment left the company in September 2010 to focus on Instapaper.