The connection between 2 of the largest public IM services is a fact …
… Microsoft announced on Wednesday that it has completed the joining of its instant messaging network with Yahoo! Messenger, meaning any of the services’ combined 350 million users can now send messages to those on either network. The interoperability was being beta tested since mid-July.
“This chapter of the story comes to a close,” said Windows Live Messenger team member Leah. “Anyone using the latest version of Windows Live Messenger or Yahoo! Messenger (in most countries) will be able to add friends, send messages and select emoticons with those from either network like crazy – and we encourage you to do so!” …
Source : BetaNews