<p>NHN Japan Corp.'s LINE free call and messaging app for smartphones has hit 100 million users worldwide, according to the company.</p><p>The app gained popularity among young people thanks to the spread of smartphones as well as its virtual stickers that users can send as part of a message.</p><p>The Japanese arm of South Korea's NHN Corp. launched the app in Japan in June 2011.</p><p>The app is now used in Indonesia, Russia, Spain, Thailand and other countries. It has about 41.51 million users in Japan.</p><p><a href="http://www.yomiuri.co.jp/dy/business/T130120003223.htm">Keep reading...</a></p>