Services Services are miniature applications that provide the actual communication functionality of the system. Services rely on the core system libraries to provide such information as what users can enter the service and what actions they can perform once there. The service itself is just a series of logic instructions that determines the generalized behaviour of data in the service. Because a service is simply a set of PHP instructions that indicate how the service works, and itself contains no data, users cannot interact with the service until a group has subscribed to it. Groups Groups are the core of the uLab technology underlying the Actua intranet site.
Users can interact only with services that are available in groups which they are a member of.
It is important to understand that when a group subscribes to a service, an instance of that service belonging to that group is created. A group can subscribe to a service more than once, thereby creating more than one instance of the service for its users. Most groups in the Actua intranet have at least two Announcements services, each one serving a different audience. A key principle in the design of the group system was flexibility. Groups have no relationship to each other, they are autonomous.