63. The system of claim 58 , wherein the data network is internet.
58. A system of providing at least one service over a data network comprising: at least one software module comprising instructions, executable by one or more processors, configured, using one or more data processing or computing devices, to create an interactive session environment for obtaining an input from a user; at least one first program comprising instructions, executable by one or more processors, configured to access at least one content, said at least one content is the output of at least one second program comprising instructions, executable by one or more processors, configured to perform: accessing or building a first one or more data structures corresponding to at least one participation matrix representing participation of ontological subjects of a first predefined order into partitions or ontological subjects of a second predefined order of a body of knowledge; accessing, or building in real time, a second one or more data structures corresponding to association strengths between a plurality of ontological subjects of a predefined order; wherein said association strength is a function of: i. probability of occurrences of some of the ontological subjects of the first order in partitions or ontological subjects of a predefined order of the body of knowledge, and ii. co-occurrences of some ontological subjects of the first order in some of partitions or ontological subjects of a predefined order; accessing evaluated, or evaluating in real time, value significances for one or more partitions or one or more ontological subjects of the body of knowledge, based on data of one or more of said first and second one or more data structures and in respect to at least one significance aspect of the one or more partitions or one or more ontological subjects of the body of knowledge; providing, using one or more data processing or computing devices, a content according to the user's input using one or more partitions of the body of knowledge based on the evaluated value significances of the one or more partitions and/or one or more ontological subjects of the body of knowledge; and at least one server computer, having at least one processing device, to respond to a user's input over a network.