Instant Messaging is a feature of the Microsoft MSN Messenger Service and Microsoft Exchange Instant Messaging Service. With Instant Messaging, you can communicate with your contacts in real time as you would in a face to face conversation. You can see whether or not a contact is online, and you have control over how your online status appears to others. For example, if you are busy and unable to talk, you can change your status to Busy.
Instant Messaging support is enabled in Microsoft Outlook by default so that you will be automatically logged on to the Instant Messaging service you installed whenever you start Outlook.
You add the Instant Messaging address of each contact who is also using Instant Messaging to the IM address box on the General tab for that contact. The online status of the contact is displayed in the InfoBar when you have the contact open. The InfoBar of an email message will also display the online status if the address displayed in the From: field is in your Instant Messaging Buddy List. You can also send an instant message by clicking the InfoBar.