Yahoo! Mail
Yahoo! Mail is an email service launched in 1997 through the American parent company Yahoo!. Yahoo Mail provides four different email plans: three for personal use (Basic, Plus, and Ad Free) and another for businesses. By December 2011, Yahoo! Mail had 281 million users, making it the third largest web-based email service in the world. Since 2015 its webmail client also supports managing non-Yahoo e-mail accounts.
Windows Live Messenger
On October 13, 2005, Yahoo! and Microsoft announced plans to add interoperability between their messenger services. The announcement came after years of third-party interoperability success (most notably, PowWow by Tribal Voice, Trillian, Pidgin) and criticisms from Tribal Voice and iCast that the major real time communications services were locking their networks. Yahoo! and Windows Live Messenger became interoperable on July 12, 2006. For six years, Yahoo! Messenger and Windows Live Messenger users in possession of up-to-date software could communicate across the two networks. Instant messaging as well as transmission of emoticons, nudges, offline messages, presence information and personal status messages were supported. On December 14, 2012, the interoperability ended.