History of Yahoo!
On March 8, 1997, Yahoo! acquired online communications company Four11. Four11's webmail service, Rocketmail, became Yahoo! Mail. Yahoo! also acquired ClassicGames.com and turned it into Yahoo! Games. Yahoo! then acquired direct marketing company Yoyodyne Entertainment, Inc. on October 12, 1998. In January 1999, Yahoo! acquired web hosting provider GeoCities. Another company Yahoo! took over was eGroups, which became Yahoo! Groups in June 2000. On March 8, 1998, Yahoo! launched Yahoo! Pager, an instant messaging service that was renamed Yahoo! Messenger a year later.
Yahoo! Publisher Network
The Yahoo! Publisher Network (abbreviated YPN) was an advertising network launched on August 2, 2005 by Yahoo! and effectively closed on April 30, 2010. The service only accepted US-Based publishers. YPN provided cost per click contextual advertising as well as various tools and services to assist publishers in building and improving their websites.