Patent ID: 8171081

Claim:
A method for exchanging internal electronic mail over an open data network within a collaborative communication system, the method comprising: maintaining a database of a plurality of users registered with the collaborative communication system, each of the users being assigned a unique identifier in the collaborative communication system, wherein the unique identifier is not an email address commonly known to include an @ sign or a user name and a domain name in the email address; causing to display on a first client machine a user directory to show at least some of the registered users when a user using the first client machine logs into the collaborative communication system, wherein each of the some of the registered users is associated with an icon; causing to display a user interface on the first client machine for authoring an internal mail, the user interface including at least a recipient area, a subject area and a message area, wherein the recipient area allows the user to select at least a recipient from the user directory to receive the internal mail, the subject area includes a topic to indicate what texts in the message area are related to; transferring the internal mail to a server in the collaborative communication system when the user decides to send the internal mail to the recipient, wherein the recipient and the user belong to a group formed by a group of members from the registered users in the collaborative communication system, the group defines a circle within which the members are allowed to communicate with each other by exchanging internal electronic mail, a member outside the group is not allowed to communicate directly with any of the members in the group; and delivering the internal mail from the server to a second client machine when the recipient logs into the collaborative communication system via the second client machine, wherein said transferring of the internal mail to the server and said delivering of the internal mail from the server to the second client machine are performed using the identifier of the user and the identifier of the recipient, without relying upon an email address.