Number of Worldwide Users of NHN Japan's Free Calling and Messaging App "LINE" Exceeds 40 Million PR Newswire TOKYO, June 6 , 2012 TOKYO, June 6 , 2012 /PRNewswire/ -- NHN Japan Corporation announced on June 6 that the number of registered users for its free calling and free messaging app 'LINE' (http://line.naver.