Yahoo and Microsoft announced that they would tear down the wall between their formerly exclusive instant messaging services and allow members to mingle beginning today.
The union of Yahoo Messenger and Windows Live Messenger systems would create the world"s largest combined IM network with nearly 350 million users, the US companies said in a joint release.
Users will need to install the latest versions of Yahoo and Live messaging software to make connections. The companies said the programs would be available for free download from their websites.
The rival Internet firms had been testing the message system link since July with "beta" software released on a limited basis.