Yahoo Inc. reportedly spied on millions of users of its popular webmail service, scanning users’ incoming emails at the behest of United States intelligence agencies. According to the report, Yahoo scanned all messages arriving via Yahoo Mail for any that contained particular sets of characters or search terms. Read more: Digital Trends Yahoo Inc last year secretly built a custom software program to search all of its customers' incoming emails for specific information provided by U.S. intelligence officials, according to people familiar with the matter. The company complied with a classified U.S. government directive, scanning hundreds of millions of Yahoo Mail accounts at the behest of the National Security Agency or FBI, said two former employees and a third person apprised of the events. Read more: Reuters.