When instant messaging (IM) with Microsoft Lync Server is available, you will be able to see the availability of other authors in the document by the color indicator to the left of the name.

By hovering over a user's availability indicator, you will expose an action box. From there, you can select one of the icons to start an IM conversation, send an e-mail, or even call the person on the phone.

The integration of UC into SharePoint and the Office applications saves you time. You don't have to switch to another application to collaborate with another author; for example, with a single click you can call the other person, send an e-mail, or start a chat conversation using IM.

Microsoft Exchange integration provides e-mail integration, while Microsoft Lync Server provides presence information, instant messaging, click-to-call, and Voice over IP (VoIP). When you use Microsoft Lync Server with VoIP, you do not need a physical phone; you can use your computer as a soft-phone.

A soft-phone is your computer giving you the capabilities of a telephone by using software and your PC. As long as you have speakers and a microphone on your PC, the Microsoft Office Communicator software will allow you to make and receive calls over the Internet.

The Microsoft Lync Server is not required by SharePoint, but adds these rich communication capabilities to a user's experience in SharePoint and in the Office applications. The preceding screenshot shows these features in a SharePoint My Site, but the same features of Presence, IM, and Telephony show up in Outlook, Word, and Excel, for example when you have Microsoft Lync Server installed.