Using this component you can have registered users and upcoming new registered users synchronized from one Joomla site to all other listed Joomla sites - no matter where the sites are located! This component is compatible with Joomla 1.0.x and Joomla 1.5.x (legacy mode) THIS VERSION IS COMPATIBLE ONLY WITH COMMUNITY BUILDER 1.1! The compatibility with CB 1.2 will be developed after the stable version of CB 1.2 is released. Synchronization is supported in the case your sites based on the different Joomla versions. But only of your sites are based only on 1.0.x versions or 1.5.x versions. Synchronization between 1.0.x and 1.5.x versions is NOT supported. User groups in Comm.Builder can be chosen. E.g. you have installed the component at the Main Site, where the user makes a new account or there are some existing registered users. In the component you list which other sites to have the user being registered on. After you have synchronized the users manually once, you don't need to do this again. New users are handled by auto - also if they change user info. BUT: It could also be the other way around: You have a subsite with registered users or new users are registered and you want them to be registered on the Main Site. There is an option to manually synchronize users from sub to main site. So there are really many ways to handle this by choosing which sites to address. The synchronization is done ON ALL THE SERVERS YOU HAVE ACCESS TO!!