Knowledge management systems (KMS) become increasingly important in periods of crises and economic slowdown, as many organizations are forced to lay off people, to reduce research and ICT budgets, to restructure departments and to optimize their costs. Subsequently, organizational knowledge assets, and mainly the existing tacit knowledge are threatened. This raises the importance of technologies that could assist organizational efforts to capture the existing knowledge and to mobilize it in order to overcome the crisis. Knowledge management systems should respond to these expectations and enable organizations dynamically to acquire and profit from all sources of knowledge. The present paper discusses the opportunities provided by extended KMS architecture combining elements of Web 2.0 technologies. It considers how Web 2.0 technologies can increase organizational effectiveness, efficiency and usability for company KM. The main services provided by KMS are identified and ranked. Finally, the paper makes an overview of the issue how KMS can enable companies to transform risks of the crises to new opportunities for further development