Microsoft has previously announced that they would be naming the version of IE7 in Windows Vista as Internet Explorer 7+. So basically it meant that IE7+ runs on Windows Vista and IE7 is running on Windows XP. Now based on user feedback, they have decided to drop the plus sign.
So the current terminology will be
* For Windows XP: Windows Internet Explorer 7 for Windows XP
* For Windows Vista: Windows Internet Explorer 7 in Windows Vista
Now there will be a uniform Internet Explorer 7 to talk about IE in general and features that are consistent across all platforms.