VoIP Drives Yahoo-Microsoft IM Deal

The announcement that Microsoft and Yahoo IM programs will interoperate is driven by one thing, and one thing alone: VoIP. It may be true that for the moment, the main communications between the two will be traditional instant messaging. But that's just the beginning. Both clients use SIP, and voice-to-voice chats between the two will be possible.

The big problem with VoIP over IM today is the limited nature of who you can reach --- only those who use the same IM program. Because of that, few people use voice chat.

This limitation has already begun to cause problems for IM makers. Upstart Skype has 53 million registered users, and 2 million people use it at any one time to make PC phone calls. With the Skype acquisition by eBay, that number will skyrocket. The more that people use Skype, the less they'll use IM programs.

Yahoo and Microsoft recognize that VoIP is the future of communications. They can't cede that future to upstarts like Skype. So they'll develop new interoperable VoIP features to their IM clients --- and expect that other IM makers will soon follow suit.