Michael Affronti is Outlook program manager at Microsoft and over on his weblog he provides a lot more detail on Outlook 12
… RSS Aggregation in Outlook is aimed at providing the user with a consistent look, feel, and experience while interacting with RSS feeds and related information. While RSS can be a complex technology to interact with, Outlook will merge the complexities and cover it with our friendly user interface. From the beginning of interacting with a feed using the subscription process through managing your feeds, their associated folder hierarchies, and potentially sharing feeds with others, Outlook will cover RSS in those situations from end-to-end. …
Read all the details on this over on Michael’s weblog