241 18 Collaborative Interfaces for the Web Saul Greenberg University of Calgary The 1960s heralded a great leap forward in the way people used computers. During that decade, people moved away from batch processing via punched cards and paper tapes to interactive online dialogues. Yet computers were expensive, and the only way to make interactive systems affordable was through time- sharing, a method that allowed many people to interact simultaneously with a single computer. A time-sharing system went to great lengths to give each user the illusion that he or she was the only person working on it (Figure 18.1a). Personal accounts and access control lists kept people’s individual filing systems separate from each other, all in the name of security. Unfortunately, these measures became barriers to collaboration. Information sharing, although possible, was heavyweight. Permissions had to be set; files had to be transferred explicitly from one user’s space to another; information had to be included in mail. The World Wide Web (WWW)—another great leap forward—has changed this process. Simply by making personal or corporate information accessible to a site’s Web server, people around the world can distribute and share information with each other. The WWW and its hypermedia structure give the illusion of one large filing system. However, significant barriers to effective collaboration remain. Although information is a shared resource, standard Web browsers are still single-user tools that partition one person from another and offer little support for people to contact each other and engage in conversation over this information (Figure 18.1b). In this chapter, I consider how this final barrier to collaboration can be removed from the WWW. I will show how Web browsers can be turned into groupware interfaces that allow people to contact each other, discuss documents, and create artifacts through their displays in real time (Figure 18.1c). Such systems are now being developed, and there is already a proliferation of Internet- based groupware systems that bring together tools including telephony, address books, text-based chat tools, electronic whiteboards, application sharing, and presentation packages. Commercial examples are the Netscape Conference tools for peer-to-peer communications (http://www.netscape.com/comprod/products/ communicator), Microsoft’s NetMeeting for multi-point conferencing (http://www.microsoft.com/netmeeting/), and Intel’s ProShare which includes video conferencing (http://www.intel.com/proshare/conferencing/). While most commercial systems are not yet well-integrated with browsers, we should expect