Defining requirements is one of the most critical activities in the development of software intensive systems. The EasyWinWin system has been very good in capturing initial requirements involving heterogeneous stakeholders in over 150 client-developer requirements negotiations. However, it has been less easy to use in updating requirements and related information as a project proceeds and adapting to the evolving nature of the requirements. Because our clients are finding that wikis are easier to learn and use, and can organize information in a flexible and updatable manner, we have developed an initial version of a WikiWinWin system as a potential successor to EasyWinWin. We have conducted a case study of WikiWinWin, and the result shows that the initial WikiWinWin is basically good at facilitating stakeholder collaborative negotiation and learning, but has some limitations that we are now addressing.