Besides being useful for finding information online, search engines like Google and Bing also save a lot of information about their users.
Follow up:Those who want to avoid this have few alternatives. However, DuckDuckGo is an alternative search engine that does not collect any user data. Since The Washington Post and The Guardian started publicizing NSA monitoring of user data at the beginning of June, the number of DuckDuckGo searches has risen sharply.
In May 2013, just prior to the Snowden revelations, it had an average of 1.8 million search queries. This increased to 4.4 million by January 2014. Whether or not alternative search engines like DuckDuckGo or Ixquick really provide protection against the curiosity of the NSA can be disputed. Unlike Google, however, at least these organizations do not report directly to the U.S. Secret Service.
You will find more statistics at Statista