Abstract: The present discloses a valued knowledge management system to automatically calculate usefulness values of particular knowledge, to display said usefulness values and to operate transactions of selected knowledge in response to selection instructions. The valued knowledge management system comprises: a usefulness assessment module to analyze content of particular knowledge, to compare fragments of particular knowledge with an accessible data and to calculate usefulness assessment value of said particular knowledge; a usefulness display module to display indication of said particular knowledge, said usefulness assessment value and description of method of said assessment; and a knowledge transaction module to operate transaction of selected knowledge in response to a selection instruction pertaining to said particular knowledge and to provide content of said knowledge after said transaction is completed.