Microsoft

Windows Live Spaces Users Get New Events, Feeds Services

Windows Live Events: Inviting Guests

Users may then select a subset of users to invite to an event from various list subsets, including their centralized Live Contacts list; Windows Live Messenger contact list; and/or Spaces Friends list. Ultimately, Microsoft is expected to use the still-announced Windows Live Groups service to allow users to invite certain categories/subgroups to an event.