The Web Distributed Computing System concept is based on the idea to have a completely client free system that can be used on every device connected to the internet and browsing the web. The other key concept is to exploit all the time the users spend surfing the web visiting pages but using only a limited amount of cpu, instead of using all the available computation power on idle time. The extremely large number of visitors, or in other word clients, is the real power of the system. The user experience is not affected by the computation, no installation needed, all the client software is embedded into pages with web2.0 technologies. Tests over 2 different systems, implemented in ajax and Flex, showed that such systems can solve various categories of problems, according with the complexity of algorithm and the amount of data need to describe the problem. Index have been defined to identify convenience in solving particular problems, to give directions on how to implement solution algorithm and problem crunching.