"Hello, Walter from the land of IE Program Managers here. You might have seen or read about the RSS functionality in the user interface of IE7 Beta 2 Preview. There is a bit more to it then just letting users subscribe and read feeds from the IE7 user interface. The RSS functionality in IE7 is "powered" by the Windows RSS Platform. The Windows RSS Platform API encapsulates 3 main components: Common Feed List, Feed Synchronization Engine, and Feed Store.
The RSS functionality in IE7 is built on top of these components. While we previously announced that the Windows RSS Platform would be available for Windows Vista, we are extremely pleased to announce that the Windows RSS Platform will also be available as part of Internet Explorer 7 for Windows XP SP2, Windows Server 2003 SP1 and Windows XP 64-bit.
The Windows RSS Platform is available to any application. The idea is that applications can utilize the Windows RSS Platform to become RSS enabled without having to re-implement basic RSS building blocks. This can significantly reduce the time and effort application developers have to invest in order to integrate RSS into their programs."
[1] http://blogs.msdn.com/ie/archive/2006/02/01/522481.aspx