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
TEK search engine search using existing search engines, downloads actual pages, and emails a subset of those pages back to the user. TEK search engine TEK is an email-based search engine developed by the TEK project at the Massachusetts Institute of Technology. The search engine enables users to search the Web using only email. It is intended to be used by people with low internet connectivity (for example, high-priced internet connection and low bandwidth connection in developing countries). TEK stands for "Time Equals Knowledge"; the search engine compensates the searching availability to the time needed for searching. To perform a web search, a