Yahoo! Messenger lets people send free, instant text and voice messages and communicate face-to-face via webcams, as well as make affordable PC-to-phone calls anywhere in the world. Instant messaging (IM) online has experienced phenomenal growth, with Yahoo! users sending approximately 17 billion messages in December 2002 alone. In 2002, Yahoo! also took the IM sensation mobile through an agreement with AT&T Wireless, which lets AT&T customers and Yahoo! Messenger desktop users initiate an instant two-way chat.
