Reputation mechanisms offer an efficient way of building the necessary level of trust in electronic markets. Feedback about an agent’s past behavior can be aggregated into a measure of reputation, and used by other agents for taking trust decisions. Unfortunately, true feedback cannot be automatically assumed. In the absence of Trusted Third Parties, the mechanism has to make it rational for agents to truthfully share reputation information. In this paper we describe two mechanisms that can be used in decentralized environments for eliciting true feedback. The mechanisms are accompanied by examples inspired by real scenarios.