Microsoft's RSS aggregator
Microsoft's MSN division has a working version of a Web-based RSS aggregator online. It appears to be part of MSN's "sandbox,'' where it tests new technologies, though it was not linked off that page as of this posting. A disclaimer at the bottom of the aggregator Web page says: "This site is not an officially supported site. It is an incubation experiment and doesn't represent any particular strategy or policy.'' Note: It seems to work best (only?) on Windows IE. You won't see much if you view it in Firefox.
UPDATE: Inside Microsoft finds MSN's Furl-like bookmarking Web site, also being tested. Note the interesting way MSN is apparently using APIs to allow you to search some of the bookmarked sites, such as Google and Amazon.
UPDATE2: The "official" announcement is here.