Search engine optimization different signals. The leading search engines, Google, Bing, and Yahoo, do not disclose the algorithms they use to rank pages. Some SEO practitioners have studied different approaches to search engine optimization, and have shared their personal opinions. Patents related to search engines can provide information to better understand search engines. In 2005, Google began personalizing search results for each user. Depending on their history of previous searches, Google crafted results for logged in users. In 2007, Google announced a campaign against paid links that transfer PageRank. On June 15, 2009, Google disclosed that they had taken measures to mitigate the
Dragonfly (search engine) Dragonfly (search engine) According to press reports, Dragonfly is an Internet search engine app being prototyped by Google that is designed to be compatible with China's state censorship provisions. Unlike a previous search engine designed by Google for use in China, Dragonfly would not notify users that results or search terms have been censored. The public learned of Dragonfly's existence in August 2018, when "The Intercept" leaked an internal memo written by a Google employee about the project. The search engine is reportedly designed to link users' phone numbers to their search queries and censor websites such as Wikipedia and