The Kindle Store is an online e-book e-commerce store operated by Amazon as part of its retail website and can be accessed from any Amazon Kindle, Fire tablet or Kindle mobile app. At the launch of the Kindle in November 2007, the store had more than 88,000 digital titles available in the U. S. store. This number increased to more than 275,000 by late 2008, and exceeded 765,000 by August 2011. In July 2014, there were over 2. 7 million titles available and as of March 2018 there are over six million titles available in the U. S. Content from the store is purchased online and downloaded using either Wi-Fi or Amazon's Whispernet to bring the content to the user's device. One of the innovations Amazon brought to the store was one-click purchasing that allowed users to quickly purchase an e-book. The Kindle Store uses a recommendation engine that looks at purchase history, browsing history, and reading activity, and then suggests material it thinks the user will like.