A few minutes ago, Microsoft flipped a switch behind the scenes, instantly removing the Social tab from the Zune software client on millions of PCs around the world. This change, of course, was not unexpected. On Wednesday, Microsoft sent out an email to Zune Music Pass subscribers informing them of upcoming changes to the service. As of today, these changes have gone into effect.

When Zune first launched, its biggest selling point was the platform’s social aspect. “Welcome to the Social” was a common tagline in advertisements, and it showcased the platform’s unique features like the ability to send and receive messages; create friends lists; share songs, albums, and playlists; and view your play history. In many ways, your play count was analogous to your Gamerscore, with some people exceeding 378,208 plays on the service (I’m looking at you, Marques). The Social allowed you to discover what your friends were listening to and even sync them to your Zune devices.

While I’m the kind of person who doesn’t like to share my play history, I always enjoyed being able to dive into the Social and see what was going on. Sadly, all good things must come to an end. With Microsoft readying Xbox Music, the next-generation of Zune, the company has made the decision to remove the old Social. There are rumors that Xbox Music will include some sort of new social element, but the old features won’t be making the transition.

The next time you open the Zune software client, you’ll receive a message informing you that “features have changed.” Once you restart the client, the Social will no longer be accessible. Some aspects of the Social are still active on Zune.net (for a limited time, of course), but many things – like profiles for users other than yourself – haven’t been working for nearly 24 hours. Other features which no longer exist include Mixview for discovering related music, channels, and the lineup of great Zune HD apps. This follows the removal of Windows Phone apps from the software earlier this year. Music videos are no longer accessible as well. Microsoft added free streaming music videos to the Zune Music Pass just under a year ago, but it was apparently short-lived. You will also be unable to re-download, re-activate, or re-license any music videos you may have previously purchased.

While it’s sad to see these features go, I know that Microsoft is paving the way for an all-new service, one that is hopefully better than ever before. Many of the details about Xbox Music and Xbox Video are still under wraps, but there have been many exciting rumors. Goodbye, Zune Social. I’ll miss you.