Increasingly, people's work is done not with pen and paper-it's done with computers. That means that one traditional way that people collaborate-by sitting down with pen and pencil and marking up each other's work-is no longer possible.

Online mark-up started with word processing programs offering simple "strikeout" and "redline" styles. Changes, however, were done sequentially, one person at a time. This often caused great delays in document production. It was also difficult to make annotations in documents, although "comment" styles were possible. Another difficulty was keeping track of who made which changes or remarks. This was improved upon by the introduction of color coding revisions by authors. Despite these advances, it was still cumbersome and time consuming for a group to work online on documents. Furthermore, while these features rapidly become common in word processing, other applications like spreadsheets didn't offer similar controls. One other problem was that all the people working on the document usually needed to have the same version of the software to work collaboratively at all.

True document collaborative possibilities emerged when someone recognized that whiteboards-a board on which special markers are used that can easily be wiped off-provided the concept that could help move online mark-up into the realm of the actually useful. These whiteboards are not physical objects set up in rooms. Instead, the whiteboard software resides on the client's desktop. Every computer screen has the ability to become a whiteboard. In addition to writing on a blank whiteboard, people can "write" directly to the documents by writing on their computer screens.

What they write is immediately visible to the other people viewing the document on their screens. People can mark up the budget by circling or otherwise marking items, each using a different color to help identify the author. Different programs also provide a variety of tools, such as erasers and spray cans. Participants can also discuss the comments as they make them.

The next generation of whiteboard applications will allow participants not only to mark up what is on each other's screens, but also to actually change the data as well. Presently, only the originator of the document conference can physically change the data. In the future, however, no doubt there will be controls that allow or restrict the changes that people participating in a whiteboard session can make. Participants will be able to talk about a budget, change the figures on the spot, and perform a "what-if" analysis. Moreover, participants will be able to do this even if they do not have the software for the file on the whiteboard. For example, if they were working on an Excel spreadsheet, they would not have to have Excel on their own computer.

How Intranet Whiteboard Applications Work

A whiteboard application refers to software which allows people to simultaneously view and annotate a document on their computer screens. Each participant would have a different color assigned so that the authorship of changes is easily visible. The participants in a whiteboard conference can also talk to each other while they are circling or otherwise pointing to the section of the document they reference in the discussion. Document conferencing by whiteboard applications allows for truly collaborative working. There are a number of companies developing this type of software. This illustration is based on how the CU-See-Me whiteboard works.

1. The CU-See-Me whiteboard works in concert with its videoconferencing software. The software works on a client/server model. People run the CU-See-Me client on their computer and they log into a special server called a reflector. When you log into a reflector, you can join any whiteboard conference found there. When someone is logged into a reflector, a signal goes out regularly from the person's computer to the reflector, telling everyone connected to the reflector that the person is logged in and available for a conference.
2. In a whiteboard conference, you can see what is on other people's computer screens, and they can see what is on your screen. You can also mark up what is on your screen or their screens by using your mouse or stylus as a drawing tool. In the same way, they can mark up what is on your screen. People participating in a whiteboard conference can see multiple screens on their computer at once-so that they can be participating in marking up several screens at the same time. People can decide to only view the markings of certain people in a whiteboard session-they can "turn off" the markings of some people.
3. When you participate in a whiteboard conference, a special protocol is used for sending data packets. The protocol allows data to be sent to many people at once, instead of having to specify sending it to an individual-that is, to multicast. The packet is sent to the reflector, which multicasts it. However, the protocol also works similarly to TCP: It checks to see whether every packet in the data has been sent. If every packet hasn't been sent, the protocol re-sends the packet until every packet is received.
4. The protocol has been designed so that it can keep resending data to those people who haven't received all the packets, but not resend to those who have received the packets. For example, if four people are participating in a whiteboard conference, and only one person hasn't received all the packets, the reflector will re-send the packets only to the individual who hasn't received all the packets.
5. The multicast protocol used by CU-See-Me allows for the whiteboard session to be broadcast to a large number of people simultaneously, and any one of those people can choose to participate in the whiteboard conference. It is also possible to participate in whiteboard sessions without having to go through a reflector. However, when reflectors aren't used, intranet administrators are not allowed to do things such as control the bandwidth used for whiteboard sessions.
6. In the future, whiteboard applications will allow people not merely to mark up documents, but to work together on the document, even if they don't have the application that created it on their own computer. People would be able to put in new figures in a spreadsheet, for example, and engage in group "what-if" scenarios, without everyone having to have the application that created the data on their own computers.