This glossary defines terminology used in Microsoft Office Communications Server 2007 R2 Group Chat SDK.


Active Chat Room Session

A session that is currently joined. All active chat room sessions can be accessed using the name and URI indexers on the GroupChatEndpoint class. When a user leaves the chat room, the session is removed from the Active Chat Room Session collection.


A small Web page or Web application that is displayed in a panel beneath the chat input area in the Group Chat client. The Group Chat client publishes a set of events and metadata about the chat room to the add-in, and permits the add-in limited access to interact with both inbound and outbound messages in a real time fashion.


Principals who have been granted IsUserAdministrator or IsChatRoomAdministrator permission. Administrators are also known as super users.


A chat message that is posted with higher than normal priority. The Group Chat client displays these messages in red, and produces a bell sound when they arrive.


A property that can be enabled on a chat room that restricts the posting of messages to members that have a presenter role.



A hierarchical construct for organizing and managing chat rooms. Categories are largely used for management of chat rooms and do not play a significant role in the user experience for the Group Chat client.

Chat Room

A persistent, topic-oriented, access-controlled forum for collaboration in which multiple users share text messages and files in real time, and have access to historical chat messages by search or by contextual history.

Chat Room Link

A hyperlink that points to a chat room. It can be entered into a current chat messages to point users to another chat room.

Chat Room Session

A class in the group chat API which can be used to join a chat room and participate in a conversation.



An approximation of a facial expression that is usually entered using punctuation characters, and often translated by text messaging applications into a small image of the corresponding facial expression.


Federated User

A group chat user who connects to Microsoft Office Communications Server through federation, and has been explicitly permissioned for group chat using the federated user administration features.

Federated User Group

A construct used to organize federated users in the group chat system. Every federated user must belong to exactly one federated user group, and that group is used to permission the federated users to the roles which they may act in while connected to group chat.


Group Chat

With Microsoft Office Communications Server 2007 R2 Group Chat, you can participate in multiparty conversations that persist over time. Conversations take place in chat rooms, which are persistent, topic oriented, access controlled forums for posting real-time messages to be shared with a group of users.



The set of contextual chat messages that users generally retrieve when they first join a chat room. History can be retrieved by context (number of recent messages desired) or by query (using parameters such as author, message content, or date).



A notification that a group chat user receives when added to a chat room. Past invitations can be requested, and will be sent in batches. Invitations are only issued when the chat room specifically enables the feature using the SendChatRoomInvitationsproperty. Due to the performance implications of large channel invites, this feature should be used sparingly.



The act of establishing a chat room session and initiating the receipt of real-time messages. A user must have a member role on a chat room in order to join.



The message that an active chat room user receives when the member role has been revoked. A kick message will remove a user from a chat room, and cease the delivery of future messages.


Large Chat Room

A chat room that has more than the server configured maximum number of active participants. The default value for the maximum number of participants is 75. Once the number of active participants exceeds this limit, the server stops sending notifications of Join and Part events when users enter or leave the chat room. The server also stops automatically sending the current active user list to new users when they enter the chat room. The server reverts to standard chat room behavior when the Large Chat Room falls below the threshold of 80% of the maximum number of active participants.



Principals (users and user groups) who have been granted a role which permits them to edit properties of a chat room or chat room category.


Principals who have been granted a role which permits them to join a chat room and participate in the conversation.



A user that is actively joined to a chat room, and receiving messages in real time.

Part (Leave)

The message that an active chat room user sends to the server when he or she wishes to stop participating in a chat room and receive real time updates. Also known as Leave.


Rights that can be granted to a principal that permit them to perform actions such as file posting and chat room administration.


Application specific user data that can be stored on the Group Chat server. The Group Chat Client uses preferences in an unpublished format to store chat rooms and display settings that the user has selected. Group Chat API developers can utilize this feature for storing any custom data or settings that they need for their application.


Principals who have been granted a role that permits them to post chat messages on a chat room that restricts chat message posting using the IsAuditorium property.


A generic term which refers to any user, user group, federated user, or federated user group.



A set of privileges which is granted to a collection of users and user groups for a specific chat room or category of chat rooms. Examples of a role include member, manager, and presenter.



A property of chat room categories. The scope of a category is defined as the list of users and user groups from which members of the category may be selected. A user cannot be a member of a chat room unless he is in scope on the parent category. The scope rules extend to all child nodes of the category, thus giving the category manager the ability to insure that no chat room in his area contains members outside of the organizations he or she wishes to collaborate with.


An object which briefly describes a chat room and the active user count of the chat room. It is returned from many of the Browse operations in the Group Chat API.


A long chat message consisting of a story title, and a long message. The long message is hidden in the chat display, but remains searchable, and viewable when user clicks the corresponding link that is shown.

A long chat message consisting of a title and a body. When the Group Chat client receives a story message, it displays only the title of the message in the chat display window as a highlighted link. When the user clicks the title, the entire message appears in a separate dialog. The content of a story message is stored in the same way as a normal chat message, and is fully searchable when querying chat history.



A one sentence description of the purpose of the chat room. The topic is displayed in the title bar of the chat room window in the Group Chat client.


User Group

An active directory container, security group, or distribution list which has been permissioned for a specific role in group chat.



A property that applies to a chat room when it is being searched for using the Group Chat API or the Group Chat client. When VisibleOnlyToMembers is set to true , only members of the chat room will find it in searches. When false , any user in scope on the category can see the chat room in a search.