Tumblr is a blogging site that began in New York City in 2007 by founders David Karp and Marco Arment. The site allows users to post text, images, videos, links, quotes and audio to a short-form blog, called a tumbleblog. Users can follow other users, or choose to make their tumblelog private. Tumblr emphasizes ease of use. The site has roughly 91.7 million posts a day and gains about 15,000 new users on a day on average. In 2013, Yahoo bought Tumblr for $1.1 billion. After the sale to Yahoo, David Karp remained as CEO.