Microsoft Analytics tracker code found!

I recently came across this piece of code on Ian Thomas' website.
As he is on the Project Gatineau team and is probably already testing the Microsoft Analytics tool, I figured he must have a piece of code on his webpages.

And he did:

<script language="javascript" type="text/javascript" src="http://x.live.com/analytics/analytics.js"></script>
<script language="javascript" type="text/javascript">
msACA.ProfileId = 'X123';
msACA.TrackPage();
</script>

I've never seen a code snippet like this and as it links to x.live.com/analytics.js which is a Microsoft domain it's probably the code Microsoft Analytics will use.

The javascript file itself contains a copyright statement: '// Copyright 2006 Microsoft Corporation. All rights reserved.'
And a quick scan through the file reveal a javascript class called 'AdCenterAnalytics'. Several function names create an idea of the features Microsoft Analytics will be providing: AddCartItem, TrackPurchase, SetView & SetGoal.

Please note, I'm not sure about this, but it all seems logical and searching for pieces of the code return nothing. Please let me know if this is from some other tracking system!