As you know Windows Live Messenger is celebrating its 10th Anniversary. On 22nd July 2009 Windows Live Messenger turned 10. Let us see its timeline which depicts some of the main milestone in its journey-
For a bigger view, please check-http://www.windowslive.com/Desktop/Messenger/Campaign/TenYear#modal-timeline
These timeline pictures are taken from UK Messenger site, which I have combined into a gif animation.
For more detailed ver. please check the UK site http://windowslive.uk.msn.com/messenger/birthday/