The new Contact.Presence property returns presence information for contacts. Previously, presence information was only available via IMAddress.Presence. The new property should simplify application development because most applications can rely on Contact.Presence.

The new Contact.DisplayName property returns the name that applications should use when rendering a contact. This property is dynamically computed based on various values including the contact's current display name as well as the user's nickname for the contact.

Windows Live Messenger enables users to provide nicknames for their contacts. Applications can now read and write nicknames using the Contact.Nickname property.

The user's Endpoints now expose their human-friendly names via the Name property. Applications can also customize the name of the local endpoint.

Improvements have been made to the reliability of the Sign-in Control. The control can be displayed and hidden using the new Show and Hide methods.

All collection types now expose an item accessor to retrieve items from the collection. Applications no longer need to enumerate through a collection to retrieve specific items.

Firefox® 3.0 is now an officially supported browser.

The DisplayPictureUrl property now returns a display picture URL for contacts. Previously, the display picture URL was only available for the signed in user.

Messenger applications often show contacts sorted by status (for example, a list of online contacts followed by a list of offline contacts). Because this is a common programming construct, it is now supported directly by the OnlineContacts and OfflineContacts properties. For more information, see How To: Monitor Presence.

The CID is an identifier for Messenger contacts. This value can now be obtained for the currently signed-in user, and all Messenger contacts, as a property of the IMAddress Class.

The SignInControlLinks property is a collection of URL strings for various Windows Live and Windows Live Messenger resources. This property is exposed through the Sign-in Control. You can use the URLs provided by this property to display links to these resources on your Web site. URL strings for the following pages are available:

• About Windows Live Messenger
  
• Change account
  
• Privacy statement
  
• Send feedback
  
• Change settings
  
• Sign Up for a Windows Live ID
  
• Terms of use
  

For more information, see How To: Access Messenger Resources.

You can access the full set of Messenger logo icons and presence icons for use in the user interface of your applications. For more information, see How To: Access Messenger Resources.

The user's current session status can now be obtained by using the User.Status property. This property indicates the following states:

• Signed out
  
• Signing in
  
• Signed in
  
• Signing out
  

For more information, see Status Property and How To: Host the Sign-in Control.

You can now modify the appearance of the Sign-in Control by setting properties of the SignInControlStyle Class.

The Sign-in Control has been updated to return extended authentication results. For example, notification is returned if an unsupported browser is in use or if a user is already signed in to Messenger. As in the previous version, authentication results are only returned if authentication succeeds. For more information, see How To: Host the Sign-in Control.

Custom presence provides a means to create custom presence properties. You can use custom presence properties to enable users to publish presence information for other users to see. For more information, see How To: Implement Presence Extensions.

Custom messaging provides a way to create custom application message types that can extend the functionality of a messaging client by facilitating the exchange of different types of data. For more information, see How To: Implement Messaging Extensions.

How To: Access Messenger Resources explains how to access Messenger URLs and Messenger Logo and Presence icons to enhance the user interface of your applications.