In my previous post, I spent some time outlining the features of Exchange Unified Messaging (UM). From time to time, I'm asked to explain how UM relates to Microsoft's Unified Communications (UC) strategy and products. In this post, I'll try to give a personal view on the relationship between UM and UC.

UM is a part of UC. In other words, UC includes UM, but UC also includes a lot of other important products and technologies. A customer who uses Microsoft's Office, SharePoint, Exchange and Office Communications Server products has an opportunity to experience many more UC scenarios than a customer using Exchange (and UM) only. Office Communications Servers' support for enterprise class presence, instant messaging and voice, combined with the ability of Office, SharePoint and Exchange to use this support, creates many useful and interesting new possibilities for the end user.

A simple example of the power and convenience of UC can be seen when a user receives a voice message (created by Exchange UM) from another user and opens it in Outlook. Not only can they listen to the message, but they can see the other user's presence status, and start an instant messaging or voice conversation with them. Not only are there more ways for users to communicate with each other, but they are woven together into an intuitive, unified experience by the software.

UC offers so many possible combinations and sequences of interactive communication that it is easy to be dazzled by the details and lose sight of the underlying principles. The user is placed at the center: they are able to communicate with others from the most convenient device, with the most appropriate method, at the right time. Unified Messaging (UM) participates in some of these scenarios (indeed, it is an integral part of many of them), but is just a component of the larger UC picture.

In the "old world", customers had a PBX and voice mail. Now, they can have a Unified Communications system, where Office Communications Server plays the part of the PBX (and much more), and Exchange Unified Messaging replaces legacy voice mail. In this "new world", many new possibilities have opened up, but some familiar patterns and interactions still occur.