Windows Messenger allows real-time communication with other people who are signed in to .NET Messenger Service. To use Windows Messenger, you must be running Windows XP.

Here are some of the things you can do using Windows Messenger:

Create a contact list of your friends, family, and coworkers.
See when your contacts are online and available, and send text messages back and forth.
Send pictures, music, or documents to your contacts.
Call a computer and have a video/voice conversation using your computer microphone, speakers, and camera.
Use ink to write instant messages (requires Windows XP Tablet PC Edition).
Invite someone to look at a program on your computer or use Whiteboard together.
Use Remote Assistance to have someone help you with your computer.