It is given a view upon interaction of computer networks and agent technologies and evaluated their roles in inprovement of decision support systems. The evolution of computer networks based on wideband and wireless technologies make possible to improve web technologies. In its turn agent technology based on the theory of multi-agent systems stimulate computer network and web technologies as well. Development of mobile devices of computer networks with enclosed mobile agents gives facilities for development ubiquitous networks based on services of semantic web, personal agents and such decision support systems suitable for majority of users. There is analysed possibilities of common use personal aăents and decision support systems under conditions of accumulative knowledge and proposed the extended strategy of decision support based on simultaneous evaluation risks and possibilities. It is considered an hypothetical example how car driver may use such method