Any potential investment assumes, from the investor's point of view, answering a legitimate question: “What is the value returned by the current investment?” Investing in the new semantic technologies in the area of Web 2.0 and Enterprise 2.0 are no exception to this rule. The research at hand combines a review of the relevant literature with action research, in order to identify coherent and relevant methods for the measurement of the benefits arising from an investment in the new wave of knowledge management and organizational memory building technologies. The paper is based on the classic ROI computation, attempting to build a new computation model, well suited to measure the success of an implementation of the informational memory. The valuation model (enforced and explained by means of a case study) may be also regarded as a measurement model for the costs and benefits of building organizational memory at the economic entity level.