The design of user interfaces for use with Web browsers represented a significant advance for client-server systems, in that they provided universal access to the user interface without any special setup apart from the installation of a Web browser. This essentially extended the client-server model to a three-tier system with universal access.
Originally, CD-ROM databases were intended as single user resources. While some progress was made in finding ways to network them, most of the networking technologies were cumbersome to implement and maintain. In the face of the development of Internet based technologies, networking CD-ROMs has simply not progressed very far.