Communications Express has an integrated user interface for calendar, mail, and address book and enables the access of one client module from another without re-authenticating user credentials.
Communication between mail and calendar is automatically established because both applications are deployed within a single web container. Also, you can optionally use Access Manager to provide the single sign-on mechanism.
Both calendar and mail applications share the same address book.
All modules share the common user preferences specified in the Options tab of Communications Express.
The Address Book Store provides horizontal scalability. See the Sun Java System Communications Express 6.3 Administration Guide for more information.
Communications Express supports virtual domains.