social browsing client is a RIA software used by users of Rhizome's web-collaboration framework, to share information and web-activities over peer-to-peer network. One of the important entities handled by social-browsing client is the "group" . Group is a framework for communication between two or more peers. There are four types of groups: 1. Contact group - created for My-Contact, and for each contact I engage with. Contacts are used for initiating communication between peers, for example when sending a request to join a session-group. These groups does not manage a persistence list of members. 2. session group : These groups are defined by user and may include two or more members that can share data with each other. This is the classic case of session-group created by user. Users can join each other groups either by requesting to join, after getting an invitation by Email, or by being invited to join, as in the case of starting a session with remote agent (e.g. virtual consultant) 3. website session groups: These groups are not defined by user, but by website owners, and are part of the dynamic settings that can be applied to social-proxy (the small widget you can see embedded in sites). Assuming that social-browsing client is always on. Now user browse some website that has integration with the framework. Social-proxy widget detect the on-line client and connect with. The information about predefined groups is transfer to client, and groups are created automatically. Now the client can manage a session with other users that connect at this time to the website. A website can define few groups, and you can imagine it to chat-rooms with few major differences: 1. User can share web-activity and not only chat media (as with regular session-group) 2. The website does not have to handle the chat or any infrastructure of chat. The chat framework , and ability to communicate with other peers is provided by social-browsing client. So you can think of this type of groups as on-demand chat service with no need to support chat (isn't that cool? ) 4. The last type of groups is the system-groups. These groups are created internally for system level communication, and user does not have control about these groups. For example, the communication between agents (advanced versions of social-browsing client) and social-hub (that receive user queries from websites) is handled by some internal groups. You can find more information about groups here: http://www.rhizomenetworks.com/social-browsing-group-management