The popular RSS feed will get extended if Microsoft has its way, as they are revealing a new format called "Simple Sharing Extensions." The format is intended to extend the standard to enable the sharing of such things as calendaring and contact lists. Microsoft intends that the technology will encompass data from a wide range of competing applications, and will not merely be "Outlook Oriented."
The idea is to use OPML (Outline Processor Markup Language), which is used to allow exchange of outline-structured information between applications and RSS, to create a new format to allow exchange of data.
Microsoft Chief Technology Officer Ray Ozzie explains that RSS on its own is not sufficient as it is essentially a 'one way' transfer mechanism aimed a broadcasting from a central point rather than his vision of a 'mesh' of feeds between many different people.