The features listed in the Collaboration settings window refer to the Stream.
Disable Collaboration Stream - This feature, defaulted on, allows the administrator to turn off Stream.
Allow Users to invite new users to Jama by email - When on, users in Stream can mention and invite users to their discussion who have not been set up in Jama. Users newly invited into Jama will automatically be given an introductory 30-day license but will only have rights to view the discussion threads to which they have been invited. Administrators can give them more rights, but will need to change the license type to a permanent one before their 30 day license expires. An organization has unlimited 30 day licenses, which have full Creator permissions.
Restrict email address to specific domains - If you would like to restrict users to invite only those in specific domains, enter the domain(s) separated by commas (e.g. jamasoftware.com, yahoo.com, yourcompany.com).
Comment Update Frequency (in seconds): This setting allows you to control how often the Stream is updated with new comments.