Microsoft introduced a hosted service that addresses the requirements of small and medium-sized businesses (SMBs).
Microsoft Solution for Hosted Messaging and Collaboration 3.0 builds on Microsoft Solution for Hosted Exchange 2003 by adding support for hosted versions of Microsoft Office Live Communications Server 2005 and Windows SharePoint Services. This enable service providers to deliver hosted enterprise-class e-mail, shared calendaring, contacts, document collaboration and instant messaging capabilities.
http://www.microsoft.com/
