• the architectural relationship they have with their clients, and
• the type of service they can provide to their clients.
• First-level services provide one-way communication for displaying information about a given agency or aspect of government.
• Second-level services provide simple two-way communication capabilities, usually for uncomplicated types of data collection such as registering comments.
• Third-level services facilitate complex transactions that may involve intragovernmental workflows and legally binding procedures. Examples of such services include voter and motor vehicle registration.
• Fourth-level services seek to integrate a wide range of services across a whole government administration, as characterized by the many emerging government portals. The eCitizen portal, developed by the government of Singapore, offers a prime example of this system type.