The term 'Popular Search Engine' can be defined by three solutions: YAHOO (5 letters), Google (6 letters), and Yahooi (6 letters). YAHOO is a web services provider founded in 1994, offering search engine services, email, news, and more. Google is a multinational technology company founded in 1998, providing search engine services, cloud computing, software, and hardware. Yahooi is a Japanese internet company founded in 1996, providing search engine services, online advertising, and e-commerce.