Electronic markets, distributed peer-to-peer applications and other forms of online collaboration are all based on mutual trust, which enables transacting peers to overcome the uncertainty and risk inherent in the environment. Reputation systems provide essential input for computational trust as predictions on future behaviour based on the past actions of a peer. In order to analyze the maturity of current reputation systems, we compare eleven reputation systems within a taxonomy of the credibility aspects of a reputation system. The taxonomy covers three topics: 1) the creation and content of a recommendation, 2) the selection and use of recommenders, and 3) the interpretation and reasoning applied to the gathered information. Although we find it possible to form a trusted reputation management network over an open network environment, there are still many regulatory and technical obstacles to address. This survey reveals various good mechanisms and methods used, but the area still requires both a) formation of standard mechanisms and metrics for reputation system collaboration and b) standard metainformation of right granularity for evaluating the credibility of reputation information provided.