Microsoft Outlook 2007 has officially adopted the Mozilla Firefox Orange RSS Icon as the standard icon for the RSS Feeds folder in Outlook 2007 (see screenshot).Microsoft Outlook 12 will have an integrated RSS newsreader like the Newsgator Outlook edition or the Attensa Outlook reader.
Microsoft Office Outlook 2007 will be using the orange icon to represent RSS throughout the product. The IE team also adopted the same Firefox RSS feed icon for IE 7.0. Source: Michael Affronti