Microsoft Office Communicator 2007 allows expansion of Exchange Server 2007

distribution lists through the Web service exposed on the server. This expansion allows

users to invite one or more individual members of the group to an IM session. Although

groups of up to 1000 members can be expanded, IM sessions can include no more than

100 members.

Also, by integrating Exchange Server 2007 with Office Communications Server 2007,

the Microsoft Office Outlook® messaging and collaboration client interface can use

presence information.