Exchange 2010 SP1 and Exchange Online (Office 365) incorporate federation to enable secure organization-to-organization free/busy and calendar sharing with other Exchange organizations. Also new is the ability for users to publish their calendar in iCal
format to anyone, and for them to subscribe to internet calendars. With Exchange now providing options for how your users can share calendar data with others inside and outside your organization, we've received a number of common questions about the differences
in setup and functionality between sharing methods. These questions and their responses below can provide clarity as you consider calendar sharing in your organization.
-David Alexander, Technical Product Manager
What is the difference between Federated Calendar Sharing and Internet Calendar Sharing, and why do Federated Sharing instead of Internet Sharing?
In Internet Calendar Sharing, can a privately shared calendar really be private? What if somebody forwards the link I sent to another person who shouldn't have access to my calendar?
How do Exchange 2010 SP1/Exchange Online (Office 365) organizations set up Federated Calendar Sharing?
Can an Exchange Online (Office 365) customer establish Federated Calendar Sharing with another Exchange Online customer, as well as a third customer who is running on-premises Exchange Server 2010 SP1?
How does setting up Internet Calendar Publishing differ for Online vs. on-premises?
When Federated Sharing is set up between Exchange 2010 SP1/Exchange Online (Office 365) organizations, will that include Federated GAL?
In Exchange Online (Office 365), is an org-org relationship required between two organizations which wish to enable Federated Calendar Sharing?
What (if any) calendar sharing or free/busy viewing capabilities do I get with federation through ADFS in Exchange 2010 SP1, vs. setting up Federated Trust with the Microsoft Federation Gateway?
How can users in my Exchange organization share calendars with users in non-Exchange organizations?
Calendar Delegates: are there other folders that could get delegated?
How can two different Exchange organizations (Org A and Org B) enable Full Calendar Sharing or org-org Free/Busy viewing?
For Office 365 organizations in a hybrid Exchange deployment (some users on-premises, some users in Exchange Online), what Free/Busy viewing and Calendar sharing options are available?